Create Record type (#10103)

# Description
This PR creates a new `Record` type to reduce duplicate code and
possibly bugs as well. (This is an edited version of #9648.)
- `Record` implements `FromIterator` and `IntoIterator` and so can be
iterated over or collected into. For example, this helps with
conversions to and from (hash)maps. (Also, no more
`cols.iter().zip(vals)`!)
- `Record` has a `push(col, val)` function to help insure that the
number of columns is equal to the number of values. I caught a few
potential bugs thanks to this (e.g. in the `ls` command).
- Finally, this PR also adds a `record!` macro that helps simplify
record creation. It is used like so:
   ```rust
   record! {
       "key1" => some_value,
       "key2" => Value::string("text", span),
       "key3" => Value::int(optional_int.unwrap_or(0), span),
       "key4" => Value::bool(config.setting, span),
   }
   ```
Since macros hinder formatting, etc., the right hand side values should
be relatively short and sweet like the examples above.

Where possible, prefer `record!` or `.collect()` on an iterator instead
of multiple `Record::push`s, since the first two automatically set the
record capacity and do less work overall.

# User-Facing Changes
Besides the changes in `nu-protocol` the only other breaking changes are
to `nu-table::{ExpandedTable::build_map, JustTable::kv_table}`.

crates/nu-command/src/strings/detect_columns.rs

@@ -6,8 +6,8 @@ use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
-    Category, Example, IntoInterruptiblePipelineData, PipelineData, Range, ShellError, Signature,
-    Span, Spanned, SyntaxShape, Type, Value,
+    Category, Example, IntoInterruptiblePipelineData, PipelineData, Range, Record, ShellError,
+    Signature, Span, Spanned, SyntaxShape, Type, Value,
 };
 
 type Input<'t> = Peekable<CharIndices<'t>>;
@@ -64,7 +64,7 @@ impl Command for DetectColumns {
                 description: "Splits string across multiple columns",
                 example: "'a b c' | detect columns -n",
                 result: Some(Value::List {
-                    vals: vec![Value::Record {
+                    vals: vec![Value::test_record(Record {
                         cols: vec![
                             "column0".to_string(),
                             "column1".to_string(),
@@ -75,8 +75,7 @@ impl Command for DetectColumns {
                             Value::test_string("b"),
                             Value::test_string("c"),
                         ],
-                        span,
-                    }],
+                    })],
                     span,
                 }),
             },
@@ -211,11 +210,7 @@ fn detect_columns(
                         };
 
                         if !(l_idx <= r_idx && (r_idx >= 0 || l_idx < (cols.len() as isize))) {
-                            return Value::Record {
-                                cols,
-                                vals,
-                                span: name_span,
-                            };
+                            return Value::record(Record { cols, vals }, name_span);
                         }
 
                         (l_idx.max(0) as usize, (r_idx as usize + 1).min(cols.len()))
@@ -228,11 +223,7 @@ fn detect_columns(
                     }
                 }
             } else {
-                return Value::Record {
-                    cols,
-                    vals,
-                    span: name_span,
-                };
+                return Value::record(Record { cols, vals }, name_span);
             };
 
             // Merge Columns
@@ -254,11 +245,7 @@ fn detect_columns(
             vals.push(binding);
             last_seg.into_iter().for_each(|v| vals.push(v));
 
-            Value::Record {
-                cols,
-                vals,
-                span: name_span,
-            }
+            Value::record(Record { cols, vals }, name_span)
         })
         .into_pipeline_data(ctrlc))
     } else {