Change the usage misnomer to "description" (#13598)

# Description
    
The meaning of the word usage is specific to describing how a command
function is *used* and not a synonym for general description. Usage can
be used to describe the SYNOPSIS or EXAMPLES sections of a man page
where the permitted argument combinations are shown or example *uses*
are given.
Let's not confuse people and call it what it is a description.

Our `help` command already creates its own *Usage* section based on the
available arguments and doesn't refer to the description with usage.

# User-Facing Changes

`help commands` and `scope commands` will now use `description` or
`extra_description`
`usage`-> `description`
`extra_usage` -> `extra_description`

Breaking change in the plugin protocol:

In the signature record communicated with the engine.
`usage`-> `description`
`extra_usage` -> `extra_description`

The same rename also takes place for the methods on
`SimplePluginCommand` and `PluginCommand`

# Tests + Formatting
- Updated plugin protocol specific changes
# After Submitting
- [ ] update plugin protocol doc

crates/nu_plugin_polars/src/cache/get.rs

@@ -21,7 +21,7 @@ impl PluginCommand for CacheGet {
         "polars store-get"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets a Dataframe or other object from the plugin cache."
     }
 

crates/nu_plugin_polars/src/cache/list.rs

@@ -15,7 +15,7 @@ impl PluginCommand for ListDF {
         "polars store-ls"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Lists stored polars objects."
     }
 

crates/nu_plugin_polars/src/cache/rm.rs

@@ -17,7 +17,7 @@ impl PluginCommand for CacheRemove {
         "polars store-rm"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Removes a stored Dataframe or other object from the plugin cache."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/append.rs

@@ -40,7 +40,7 @@ impl PluginCommand for AppendDF {
         "polars append"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Appends a new dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/cast.rs

@@ -22,7 +22,7 @@ impl PluginCommand for CastDF {
         "polars cast"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Cast a column to a different dtype."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/columns.rs

@@ -16,7 +16,7 @@ impl PluginCommand for ColumnsDF {
         "polars columns"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Show dataframe columns."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/drop.rs

@@ -20,7 +20,7 @@ impl PluginCommand for DropDF {
         "polars drop"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a new dataframe by dropping the selected columns."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/drop_duplicates.rs

@@ -21,7 +21,7 @@ impl PluginCommand for DropDuplicates {
         "polars drop-duplicates"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Drops duplicate values in dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/drop_nulls.rs

@@ -20,7 +20,7 @@ impl PluginCommand for DropNulls {
         "polars drop-nulls"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Drops null values in dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/dummies.rs

@@ -16,7 +16,7 @@ impl PluginCommand for Dummies {
         "polars dummies"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a new dataframe with dummy variables."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/filter_with.rs

@@ -23,7 +23,7 @@ impl PluginCommand for FilterWith {
         "polars filter-with"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Filters dataframe using a mask or expression as reference."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/first.rs

@@ -20,7 +20,7 @@ impl PluginCommand for FirstDF {
         "polars first"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Show only the first number of rows or create a first expression"
     }
 

crates/nu_plugin_polars/src/dataframe/eager/get.rs

@@ -20,7 +20,7 @@ impl PluginCommand for GetDF {
         "polars get"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates dataframe with the selected columns."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/last.rs

@@ -20,7 +20,7 @@ impl PluginCommand for LastDF {
         "polars last"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates new dataframe with tail rows or creates a last expression."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/open.rs

@@ -45,7 +45,7 @@ impl PluginCommand for OpenDataFrame {
         "polars open"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Opens CSV, JSON, NDJSON/JSON lines, arrow, avro, or parquet file to create dataframe. A lazy dataframe will be created by default, if supported."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/pivot.rs

@@ -24,7 +24,7 @@ impl PluginCommand for PivotDF {
         "polars pivot"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Pivot a DataFrame from wide to long format."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/query_df.rs

@@ -24,7 +24,7 @@ impl PluginCommand for QueryDf {
         "polars query"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Query dataframe using SQL. Note: The dataframe is always named 'df' in your query's from clause."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/rename.rs

@@ -22,7 +22,7 @@ impl PluginCommand for RenameDF {
         "polars rename"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Rename a dataframe column."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/sample.rs

@@ -20,7 +20,7 @@ impl PluginCommand for SampleDF {
         "polars sample"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Create sample dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/save/mod.rs

@@ -29,7 +29,7 @@ impl PluginCommand for SaveDF {
         "polars save"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Saves a dataframe to disk. For lazy dataframes a sink operation will be used if the file type supports it (parquet, ipc/arrow, csv, and ndjson)."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/schema.rs

@@ -15,7 +15,7 @@ impl PluginCommand for SchemaCmd {
         "polars schema"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Show schema for a dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/shape.rs

@@ -17,7 +17,7 @@ impl PluginCommand for ShapeDF {
         "polars shape"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Shows column and row size for a dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/slice.rs

@@ -18,7 +18,7 @@ impl PluginCommand for SliceDF {
         "polars slice"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates new dataframe from a slice of rows."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/summary.rs

@@ -25,7 +25,7 @@ impl PluginCommand for Summary {
         "polars summary"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "For a dataframe, produces descriptive statistics (summary statistics) for its numeric columns."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/take.rs

@@ -19,7 +19,7 @@ impl PluginCommand for TakeDF {
         "polars take"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates new dataframe using the given indices."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/to_df.rs

@@ -25,7 +25,7 @@ impl PluginCommand for ToDataFrame {
         "polars into-df"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Converts a list, table or record into a dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/to_nu.rs

@@ -22,7 +22,7 @@ impl PluginCommand for ToNu {
         "polars into-nu"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Converts a dataframe or an expression into nushell value for access and exploration."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/unpivot.rs

@@ -23,7 +23,7 @@ impl PluginCommand for UnpivotDF {
         "polars unpivot"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Unpivot a DataFrame from wide to long format."
     }
 

crates/nu_plugin_polars/src/dataframe/eager/with_column.rs

@@ -20,7 +20,7 @@ impl PluginCommand for WithColumn {
         "polars with-column"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Adds a series to the dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/alias.rs

@@ -17,7 +17,7 @@ impl PluginCommand for ExprAlias {
         "polars as"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates an alias expression."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/arg_where.rs

@@ -19,7 +19,7 @@ impl PluginCommand for ExprArgWhere {
         "polars arg-where"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates an expression that returns the arguments where expression is true."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/col.rs

@@ -15,7 +15,7 @@ impl PluginCommand for ExprCol {
         "polars col"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a named column expression."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/concat_str.rs

@@ -19,7 +19,7 @@ impl PluginCommand for ExprConcatStr {
         "polars concat-str"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a concat string expression."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/datepart.rs

@@ -27,7 +27,7 @@ impl PluginCommand for ExprDatePart {
         "polars datepart"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates an expression for capturing the specified datepart in a column."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/expressions_macro.rs

@@ -21,13 +21,13 @@ macro_rules! expr_command {
                 $name
             }
 
-            fn usage(&self) -> &str {
+            fn description(&self) -> &str {
                 $desc
             }
 
             fn signature(&self) -> Signature {
                 Signature::build(self.name())
-                    .usage($desc)
+                    .description($desc)
                     .input_output_type(
                         Type::Custom("expression".into()),
                         Type::Custom("expression".into()),
@@ -76,7 +76,7 @@ macro_rules! expr_command {
 
             fn signature(&self) -> Signature {
                 Signature::build(self.name())
-                    .usage($desc)
+                    .description($desc)
                     .input_output_type(
                         Type::Custom("expression".into()),
                         Type::Custom("expression".into()),
@@ -127,13 +127,13 @@ macro_rules! lazy_expr_command {
                 $name
             }
 
-            fn usage(&self) -> &str {
+            fn description(&self) -> &str {
                 $desc
             }
 
             fn signature(&self) -> Signature {
                 Signature::build(self.name())
-                    .usage($desc)
+                    .description($desc)
                     .input_output_types(vec![
                         (
                             Type::Custom("expression".into()),
@@ -199,7 +199,7 @@ macro_rules! lazy_expr_command {
                 $name
             }
 
-            fn usage(&self) -> &str {
+            fn description(&self) -> &str {
                 $desc
             }
             fn signature(&self) -> Signature {

crates/nu_plugin_polars/src/dataframe/expressions/is_in.rs

@@ -20,7 +20,7 @@ impl PluginCommand for ExprIsIn {
         "polars is-in"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates an is-in expression or checks to see if the elements are contained in the right series"
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/lit.rs

@@ -14,7 +14,7 @@ impl PluginCommand for ExprLit {
         "polars lit"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a literal expression."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/otherwise.rs

@@ -17,7 +17,7 @@ impl PluginCommand for ExprOtherwise {
         "polars otherwise"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Completes a when expression."
     }
 

crates/nu_plugin_polars/src/dataframe/expressions/when.rs

@@ -19,7 +19,7 @@ impl PluginCommand for ExprWhen {
         "polars when"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates and modifies a when expression."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/aggregate.rs

@@ -21,7 +21,7 @@ impl PluginCommand for LazyAggregate {
         "polars agg"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Performs a series of aggregations from a group-by."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/collect.rs

@@ -17,7 +17,7 @@ impl PluginCommand for LazyCollect {
         "polars collect"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Collect lazy dataframe into eager dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/explode.rs

@@ -18,7 +18,7 @@ impl PluginCommand for LazyExplode {
         "polars explode"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Explodes a dataframe or creates a explode expression."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/fetch.rs

@@ -17,7 +17,7 @@ impl PluginCommand for LazyFetch {
         "polars fetch"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Collects the lazyframe to the selected rows."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/fill_nan.rs

@@ -19,7 +19,7 @@ impl PluginCommand for LazyFillNA {
         "polars fill-nan"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Replaces NaN values with the given expression."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/fill_null.rs

@@ -19,7 +19,7 @@ impl PluginCommand for LazyFillNull {
         "polars fill-null"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Replaces NULL values with the given expression."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/filter.rs

@@ -20,7 +20,7 @@ impl PluginCommand for LazyFilter {
         "polars filter"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Filter dataframe based in expression."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/flatten.rs

@@ -21,7 +21,7 @@ impl PluginCommand for LazyFlatten {
         "polars flatten"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "An alias for polars explode."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/groupby.rs

@@ -20,7 +20,7 @@ impl PluginCommand for ToLazyGroupBy {
         "polars group-by"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a group-by object that can be used for other aggregations."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/join.rs

@@ -20,7 +20,7 @@ impl PluginCommand for LazyJoin {
         "polars join"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Joins a lazy frame with other lazy frame."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/macro_commands.rs

@@ -19,13 +19,13 @@ macro_rules! lazy_command {
                 $name
             }
 
-            fn usage(&self) -> &str {
+            fn description(&self) -> &str {
                 $desc
             }
 
             fn signature(&self) -> Signature {
                 Signature::build(self.name())
-                    .usage($desc)
+                    .description($desc)
                     .input_output_type(
                         Type::Custom("dataframe".into()),
                         Type::Custom("dataframe".into()),
@@ -74,7 +74,7 @@ macro_rules! lazy_command {
 
             fn signature(&self) -> Signature {
                 Signature::build($name)
-                    .usage($desc)
+                    .description($desc)
                     .input_output_type(
                         Type::Custom("dataframe".into()),
                         Type::Custom("dataframe".into()),
@@ -122,7 +122,7 @@ macro_rules! lazy_command {
                 $name
             }
 
-            fn usage(&self) -> &str {
+            fn description(&self) -> &str {
                 $desc
             }
             fn signature(&self) -> Signature {

crates/nu_plugin_polars/src/dataframe/lazy/median.rs

@@ -19,7 +19,7 @@ impl PluginCommand for LazyMedian {
         "polars median"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Median value from columns in a dataframe or creates expression for an aggregation"
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/quantile.rs

@@ -22,7 +22,7 @@ impl PluginCommand for LazyQuantile {
         "polars quantile"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Aggregates the columns to the selected quantile."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/select.rs

@@ -18,7 +18,7 @@ impl PluginCommand for LazySelect {
         "polars select"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Selects columns from lazyframe."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/sort_by_expr.rs

@@ -21,7 +21,7 @@ impl PluginCommand for LazySortBy {
         "polars sort-by"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Sorts a lazy dataframe based on expression(s)."
     }
 

crates/nu_plugin_polars/src/dataframe/lazy/to_lazy.rs

@@ -15,7 +15,7 @@ impl PluginCommand for ToLazyFrame {
         "polars into-lazy"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Converts a dataframe into a lazy dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/series/all_false.rs

@@ -17,7 +17,7 @@ impl PluginCommand for AllFalse {
         "polars all-false"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns true if all values are false."
     }
 

crates/nu_plugin_polars/src/dataframe/series/all_true.rs

@@ -17,7 +17,7 @@ impl PluginCommand for AllTrue {
         "polars all-true"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns true if all values are true."
     }
 

crates/nu_plugin_polars/src/dataframe/series/arg_max.rs

@@ -18,7 +18,7 @@ impl PluginCommand for ArgMax {
         "polars arg-max"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Return index for max value in series."
     }
 

crates/nu_plugin_polars/src/dataframe/series/arg_min.rs

@@ -18,7 +18,7 @@ impl PluginCommand for ArgMin {
         "polars arg-min"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Return index for min value in series."
     }
 

crates/nu_plugin_polars/src/dataframe/series/cumulative.rs

@@ -51,7 +51,7 @@ impl PluginCommand for Cumulative {
         "polars cumulative"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Cumulative calculation for a series."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/as_date.rs

@@ -18,11 +18,11 @@ impl PluginCommand for AsDate {
         "polars as-date"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         r#"Converts string to date."#
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"Format example:
         "%Y-%m-%d"    => 2021-12-31
         "%d-%m-%Y"    => 31-12-2021

crates/nu_plugin_polars/src/dataframe/series/date/as_datetime.rs

@@ -20,11 +20,11 @@ impl PluginCommand for AsDateTime {
         "polars as-datetime"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         r#"Converts string to datetime."#
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"Format example:
         "%y/%m/%d %H:%M:%S"  => 21/12/31 12:54:98
         "%y-%m-%d %H:%M:%S"  => 2021-12-31 24:58:01

crates/nu_plugin_polars/src/dataframe/series/date/get_day.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetDay {
         "polars get-day"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets day from date."
     }
 
@@ -58,7 +58,7 @@ impl PluginCommand for GetDay {
         command(plugin, engine, call, input).map_err(LabeledError::from)
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         ""
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_hour.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetHour {
         "polars get-hour"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets hour from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_minute.rs

@@ -19,7 +19,7 @@ impl PluginCommand for GetMinute {
         "polars get-minute"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets minute from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_month.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetMonth {
         "polars get-month"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets month from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_nanosecond.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetNanosecond {
         "polars get-nanosecond"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets nanosecond from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_ordinal.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetOrdinal {
         "polars get-ordinal"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets ordinal from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_second.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetSecond {
         "polars get-second"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets second from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_week.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetWeek {
         "polars get-week"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets week from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_weekday.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetWeekDay {
         "polars get-weekday"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets weekday from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/date/get_year.rs

@@ -21,7 +21,7 @@ impl PluginCommand for GetYear {
         "polars get-year"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Gets year from date."
     }
 

crates/nu_plugin_polars/src/dataframe/series/indexes/arg_sort.rs

@@ -18,7 +18,7 @@ impl PluginCommand for ArgSort {
         "polars arg-sort"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns indexes for a sorted series."
     }
 

crates/nu_plugin_polars/src/dataframe/series/indexes/arg_true.rs

@@ -18,7 +18,7 @@ impl PluginCommand for ArgTrue {
         "polars arg-true"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns indexes where values are true."
     }
 

crates/nu_plugin_polars/src/dataframe/series/indexes/arg_unique.rs

@@ -18,7 +18,7 @@ impl PluginCommand for ArgUnique {
         "polars arg-unique"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns indexes for unique values."
     }
 

crates/nu_plugin_polars/src/dataframe/series/indexes/set_with_idx.rs

@@ -22,7 +22,7 @@ impl PluginCommand for SetWithIndex {
         "polars set-with-idx"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Sets value in the given index."
     }
 

crates/nu_plugin_polars/src/dataframe/series/masks/is_duplicated.rs

@@ -18,7 +18,7 @@ impl PluginCommand for IsDuplicated {
         "polars is-duplicated"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates mask indicating duplicated values."
     }
 

crates/nu_plugin_polars/src/dataframe/series/masks/is_not_null.rs

@@ -20,7 +20,7 @@ impl PluginCommand for IsNotNull {
         "polars is-not-null"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates mask where value is not null."
     }
 

crates/nu_plugin_polars/src/dataframe/series/masks/is_null.rs

@@ -22,7 +22,7 @@ impl PluginCommand for IsNull {
         "polars is-null"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates mask where value is null."
     }
 

crates/nu_plugin_polars/src/dataframe/series/masks/is_unique.rs

@@ -18,7 +18,7 @@ impl PluginCommand for IsUnique {
         "polars is-unique"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates mask indicating unique values."
     }
 

crates/nu_plugin_polars/src/dataframe/series/masks/not.rs

@@ -19,7 +19,7 @@ impl PluginCommand for NotSeries {
         "polars not"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Inverts boolean mask."
     }
 

crates/nu_plugin_polars/src/dataframe/series/masks/set.rs

@@ -19,7 +19,7 @@ impl PluginCommand for SetSeries {
         "polars set"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Sets value where given mask is true."
     }
 

crates/nu_plugin_polars/src/dataframe/series/n_null.rs

@@ -17,7 +17,7 @@ impl PluginCommand for NNull {
         "polars count-null"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Counts null values."
     }
 

crates/nu_plugin_polars/src/dataframe/series/n_unique.rs

@@ -19,7 +19,7 @@ impl PluginCommand for NUnique {
         "polars n-unique"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Counts unique values."
     }
 

crates/nu_plugin_polars/src/dataframe/series/rolling.rs

@@ -53,7 +53,7 @@ impl PluginCommand for Rolling {
         "polars rolling"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Rolling calculation for a series."
     }
 

crates/nu_plugin_polars/src/dataframe/series/shift.rs

@@ -24,7 +24,7 @@ impl PluginCommand for Shift {
         "polars shift"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Shifts the values by a given period."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/concatenate.rs

@@ -19,7 +19,7 @@ impl PluginCommand for Concatenate {
         "polars concatenate"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Concatenates strings with other array."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/contains.rs

@@ -19,7 +19,7 @@ impl PluginCommand for Contains {
         "polars contains"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Checks if a pattern is contained in a string."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/replace.rs

@@ -19,7 +19,7 @@ impl PluginCommand for Replace {
         "polars replace"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Replace the leftmost (sub)string by a regex pattern."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/replace_all.rs

@@ -19,7 +19,7 @@ impl PluginCommand for ReplaceAll {
         "polars replace-all"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Replace all (sub)strings by a regex pattern."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/str_lengths.rs

@@ -18,7 +18,7 @@ impl PluginCommand for StrLengths {
         "polars str-lengths"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Get lengths of all strings."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/str_slice.rs

@@ -22,7 +22,7 @@ impl PluginCommand for StrSlice {
         "polars str-slice"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Slices the string from the start position until the selected length."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/strftime.rs

@@ -19,7 +19,7 @@ impl PluginCommand for StrFTime {
         "polars strftime"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Formats date based on string rule."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/to_lowercase.rs

@@ -18,7 +18,7 @@ impl PluginCommand for ToLowerCase {
         "polars lowercase"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Lowercase the strings in the column."
     }
 

crates/nu_plugin_polars/src/dataframe/series/string/to_uppercase.rs

@@ -18,7 +18,7 @@ impl PluginCommand for ToUpperCase {
         "polars uppercase"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Uppercase the strings in the column."
     }
 

crates/nu_plugin_polars/src/dataframe/series/unique.rs

@@ -23,7 +23,7 @@ impl PluginCommand for Unique {
         "polars unique"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns unique values from a dataframe."
     }
 

crates/nu_plugin_polars/src/dataframe/series/value_counts.rs

@@ -20,7 +20,7 @@ impl PluginCommand for ValueCount {
         "polars value-counts"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns a dataframe with the counts for unique values in series."
     }
 

crates/nu_plugin_polars/src/dataframe/stub.rs

@@ -13,7 +13,7 @@ impl PluginCommand for PolarsCmd {
         "polars"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Operate with data in a dataframe format."
     }
 
@@ -23,7 +23,7 @@ impl PluginCommand for PolarsCmd {
             .input_output_types(vec![(Type::Nothing, Type::String)])
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "You must use one of the following subcommands. Using this command as-is will only produce this help message."
     }