ansi -l includes previews of attributes (e.g., bold, dimmed, blink, etc.) (#14196)

# Description

A few simple changes:

* Extends the range of previews to include the attributes - Bold,
italic, underline, etc.
* Also resets the colors before *every* preview. Previously we weren't
doing this, so the "string" theme color was bleeding into a few previews
(mostly, if not all, `bg` ones). Now the "default foreground" color is
used for any preview without an explicit foreground color.
* Moves the preview code into the `if use_ansi_coloring` block as a
stupid-nitpick optimization. There's no reason to populate the previews
when they are explicitly not shown with `use_ansi_coloring: false`.
* Moves `reset` to the bottom of the attribute list so that it isn't
previewed. This is a bit of a nitpick as well since internally we send
the same code for both a `reset` and `attr_normal` (which is correct),
but semantically a `reset` doesn't seem like a "previewable" thing,
whereas "normal" text can be demonstrated with a preview.

# User-Facing Changes

`ansi -l` now shows additional previews

# Tests + Formatting

- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting

N/A

crates/nu-command/src/platform/ansi/ansi_.rs

@@ -425,8 +425,6 @@ static CODE_LIST: Lazy<Vec<AnsiCode>> = Lazy::new(|| { vec![
     AnsiCode { short_name: Some("grey89"), long_name: "xterm_grey89", code: Color::Fixed(254).prefix().to_string()},
     AnsiCode { short_name: Some("grey93"), long_name: "xterm_grey93", code: Color::Fixed(255).prefix().to_string()},
 
-    AnsiCode{ short_name: None, long_name: "reset", code: "\x1b[0m".to_owned()},
-
     // Attributes
     AnsiCode { short_name: Some("n"), long_name: "attr_normal", code: Color::Green.suffix().to_string()},
     AnsiCode { short_name: Some("bo"), long_name: "attr_bold", code: Style::new().bold().prefix().to_string()},
@@ -437,6 +435,8 @@ static CODE_LIST: Lazy<Vec<AnsiCode>> = Lazy::new(|| { vec![
     AnsiCode { short_name: Some("h"), long_name: "attr_hidden", code: Style::new().hidden().prefix().to_string()},
     AnsiCode { short_name: Some("s"), long_name: "attr_strike", code: Style::new().strikethrough().prefix().to_string()},
 
+    AnsiCode{ short_name: None, long_name: "reset", code: "\x1b[0m".to_owned()},
+
     // Reference for ansi codes https://gist.github.com/fnky/458719343aabd01cfb17a3a4f7296797
     // Another good reference http://ascii-table.com/ansi-escape-sequences.php
 
@@ -842,15 +842,19 @@ fn generate_ansi_code_list(
         .map(move |(i, ansi_code)| {
             let name = Value::string(ansi_code.long_name, call_span);
             let short_name = Value::string(ansi_code.short_name.unwrap_or(""), call_span);
-            // The first 102 items in the ansi array are colors
-            let preview = if i < 389 {
-                Value::string(format!("{}NUSHELL\u{1b}[0m", &ansi_code.code), call_span)
-            } else {
-                Value::string("\u{1b}[0m", call_span)
-            };
             let code = Value::string(ansi_code.code.replace('\u{1b}', "\\e"), call_span);
 
             let record = if use_ansi_coloring {
+                // The first 397 items in the ansi array are previewable
+                let preview = if i < 397 {
+                    Value::string(
+                        format!("\u{1b}[0m{}NUSHELL\u{1b}[0m", &ansi_code.code),
+                        call_span,
+                    )
+                } else {
+                    Value::string("\u{1b}[0m", call_span)
+                };
+
                 record! {
                     "name" => name,
                     "preview" => preview,