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/charting/histogram.rs

@@ -4,11 +4,10 @@ use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, Spanned,
-    SyntaxShape, Type, Value,
+    Category, Example, IntoPipelineData, PipelineData, Record, ShellError, Signature, Span,
+    Spanned, SyntaxShape, Type, Value,
 };
 use std::collections::HashMap;
-use std::iter;
 
 #[derive(Clone)]
 pub struct Histogram;
@@ -53,7 +52,7 @@ impl Command for Histogram {
                 description: "Compute a histogram for a list of numbers",
                 example: "[1 2 1] | histogram",
                 result: Some(Value::List {
-                        vals: vec![Value::Record {
+                        vals: vec![Value::test_record(Record {
                             cols: vec!["value".to_string(), "count".to_string(), "quantile".to_string(), "percentage".to_string(), "frequency".to_string()],
                             vals: vec![
                                 Value::test_int(1),
@@ -62,9 +61,8 @@ impl Command for Histogram {
                                 Value::test_string("66.67%"),
                                 Value::test_string("******************************************************************"),
                             ],
-                            span: Span::test_data(),
-                        },
-                        Value::Record {
+                        }),
+                        Value::test_record(Record {
                             cols: vec!["value".to_string(), "count".to_string(), "quantile".to_string(), "percentage".to_string(), "frequency".to_string()],
                             vals: vec![
                                 Value::test_int(2),
@@ -73,8 +71,7 @@ impl Command for Histogram {
                                 Value::test_string("33.33%"),
                                 Value::test_string("*********************************"),
                             ],
-                            span: Span::test_data(),
-                        }],
+                        })],
                         span: Span::test_data(),
                     }
                  ),
@@ -195,8 +192,8 @@ fn run_histogram(
             for v in values {
                 match v {
                     // parse record, and fill valid value to actual input.
-                    Value::Record { cols, vals, .. } => {
-                        for (c, v) in iter::zip(cols, vals) {
+                    Value::Record { val, .. } => {
+                        for (c, v) in val {
                             if &c == col_name {
                                 if let Ok(v) = HashableValue::from_value(v, head_span) {
                                     inputs.push(v);
@@ -272,23 +269,25 @@ fn histogram_impl(
 
         result.push((
             count, // attach count first for easily sorting.
-            Value::Record {
-                cols: result_cols.clone(),
-                vals: vec![
-                    val.into_value(),
-                    Value::Int { val: count, span },
-                    Value::Float {
-                        val: quantile,
-                        span,
-                    },
-                    Value::String {
-                        val: percentage,
-                        span,
-                    },
-                    Value::String { val: freq, span },
-                ],
+            Value::record(
+                Record {
+                    cols: result_cols.clone(),
+                    vals: vec![
+                        val.into_value(),
+                        Value::Int { val: count, span },
+                        Value::Float {
+                            val: quantile,
+                            span,
+                        },
+                        Value::String {
+                            val: percentage,
+                            span,
+                        },
+                        Value::String { val: freq, span },
+                    ],
+                },
                 span,
-            },
+            ),
         ));
     }
     result.sort_by(|a, b| b.0.cmp(&a.0));