docs: Apply documentation standards across all docs (#49177)

## Summary

Comprehensive remediation of 146 documentation files to align with Zed's
documentation conventions and brand voice guidelines.

## Changes

### YAML Frontmatter
- Added `title` and `description` frontmatter to all docs missing it

### Settings UI Pattern
- Updated 48+ files to show Settings Editor before JSON examples
- Pattern: `Configure X in Settings ({#kb zed::OpenSettings}), or add to
your settings file:`
- Added `([how to edit](./configuring-zed.md#settings-files))` links for
JSON-only settings

### Brand Voice Fixes
- Removed exclamation points (command-palette, key-bindings, repl,
privacy-and-security, etc.)
- Simplified em dash chains to parentheticals (environment,
troubleshooting, agent-panel, etc.)
- Fixed marketing language (yarn.md intro, development/linux.md)

### Terminology Alignment
- `settings UI` -> `Settings Editor`
- `sidebar` -> specific panel names (Project Panel, Collab Panel)
- `directory` -> `folder` in non-technical contexts
- `workspace` -> `project` in non-LSP contexts
- `Command Palette` -> `command palette` (lowercase)

### Callout Standardization
- Converted various callout formats to standard `> **Note:**` pattern

## Related

Depends on conventions established in #49176.

Release Notes:

- N/A

docs/src/languages/elixir.md

@@ -1,3 +1,8 @@
+---
+title: Elixir
+description: "Configure Elixir language support in Zed, including language servers, formatting, and debugging."
+---
+
 # Elixir
 
 Elixir support is available through the [Elixir extension](https://github.com/zed-extensions/elixir).
@@ -19,7 +24,7 @@ The Elixir extension offers language server support for `expert`, `elixir-ls`, `
 
 ### Expert
 
-To switch to `expert`, add the following to your `settings.json`:
+Configure language servers in Settings ({#kb zed::OpenSettings}) under Languages > Elixir, or add to your settings file:
 
 ```json [settings]
   "languages": {
@@ -34,7 +39,7 @@ To switch to `expert`, add the following to your `settings.json`:
 
 ### Next LS
 
-To switch to `next-ls`, add the following to your `settings.json`:
+Configure language servers in Settings ({#kb zed::OpenSettings}) under Languages > Elixir, or add to your settings file:
 
 ```json [settings]
   "languages": {
@@ -49,7 +54,7 @@ To switch to `next-ls`, add the following to your `settings.json`:
 
 ### Lexical
 
-To switch to `lexical`, add the following to your `settings.json`:
+Configure language servers in Settings ({#kb zed::OpenSettings}) under Languages > Elixir, or add to your settings file:
 
 ```json [settings]
   "languages": {
@@ -82,7 +87,9 @@ brew install elixir-ls
 
 ### Formatting with Mix
 
-If you prefer to format your code with [Mix](https://hexdocs.pm/mix/Mix.html), use the following snippet in your `settings.json` file to configure it as an external formatter. Formatting will occur on file save.
+If you prefer to format your code with [Mix](https://hexdocs.pm/mix/Mix.html), configure it as an external formatter. Formatting will occur on file save.
+
+Configure formatting in Settings ({#kb zed::OpenSettings}) under Languages > Elixir, or add to your settings file:
 
 ```json [settings]
 {
@@ -102,7 +109,7 @@ If you prefer to format your code with [Mix](https://hexdocs.pm/mix/Mix.html), u
 
 ### Additional workspace configuration options
 
-You can pass additional elixir-ls workspace configuration options via lsp settings in `settings.json`.
+You can pass additional elixir-ls workspace configuration options via `lsp` settings in your settings file ([how to edit](../configuring-zed.md#settings-files)).
 
 The following example disables dialyzer:
 
@@ -126,7 +133,7 @@ Zed also supports HEEx templates. HEEx is a mix of [EEx](https://hexdocs.pm/eex/
 
 #### Using the Tailwind CSS Language Server with HEEx
 
-To get all the features (autocomplete, linting, etc.) from the [Tailwind CSS language server](https://github.com/tailwindlabs/tailwindcss-intellisense/tree/HEAD/packages/tailwindcss-language-server#readme) in HEEx files, you need to configure the language server so that it knows about where to look for CSS classes by adding the following to your `settings.json`:
+To get all features (autocomplete, linting, and hover docs) from the [Tailwind CSS language server](https://github.com/tailwindlabs/tailwindcss-intellisense/tree/HEAD/packages/tailwindcss-language-server#readme) in HEEx files, add the following to your settings file ([how to edit](../configuring-zed.md#settings-files)):
 
 ```json [settings]
 {