Fix command descriptions+examples (#5129)

* Fix exit usage

* Move dfr as-date* format examples to extra_usage

* Update command usage and examples

* More docs on `str trim`

Co-authored-by: sholderbach <sholderbach@users.noreply.github.com>

crates/nu-command/src/conversions/fmt.rs

@@ -14,7 +14,7 @@ impl Command for Fmt {
     }
 
     fn usage(&self) -> &str {
-        "format numbers"
+        "Format a number"
     }
 
     fn signature(&self) -> nu_protocol::Signature {
@@ -23,7 +23,7 @@ impl Command for Fmt {
 
     fn examples(&self) -> Vec<Example> {
         vec![Example {
-            description: "format numbers",
+            description: "Get a record containing multiple formats for the number 42",
             example: "42 | fmt",
             result: Some(Value::Record {
                 cols: vec![

crates/nu-command/src/conversions/into/command.rs

@@ -18,7 +18,7 @@ impl Command for Into {
     }
 
     fn usage(&self) -> &str {
-        "Apply into function."
+        "Commands to convert data from one type to another."
     }
 
     fn run(

crates/nu-command/src/conversions/into/datetime.rs

@@ -101,7 +101,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "converts text into datetime"
+        "Convert text into a datetime"
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/conversions/into/decimal.rs

@@ -22,7 +22,7 @@ impl Command for SubCommand {
     }
 
     fn usage(&self) -> &str {
-        "converts text into decimal"
+        "Convert text into a decimal"
     }
 
     fn run(