Support bracket colorization (rainbow brackets) (#43172)

Deals with https://github.com/zed-industries/zed/issues/5259

Highlights brackets with different colors based on their depth.
Uses existing tree-sitter queries from brackets.scm to find brackets,
uses theme's accents to color them.


https://github.com/user-attachments/assets/cc5f3aba-22fa-446d-9af7-ba6e772029da

1. Adds `colorize_brackets` language setting that allows, per language
or globally for all languages, to configure whether Zed should color the
brackets for a particular language.

Disabled for all languages by default.

2. Any given language can opt-out a certain bracket pair by amending the
brackets.scm like `("\"" @open "\"" @close) ` -> `(("\"" @open "\""
@close) (#set! rainbow.exclude))`

3. Brackets are using colors from theme accents, which can be overridden
as

```jsonc
"theme_overrides": {
  "One Dark": {
    "accents": ["#ff69b4", "#7fff00", "#ff1493", "#00ffff", "#ff8c00", "#9400d3"]
  }
},
```

Release Notes:

- Added bracket colorization (rainbow brackets) support. Use
`colorize_brackets` language setting to enable.

---------

Co-authored-by: MrSubidubi <dev@bahn.sh>
Co-authored-by: Lukas Wirth <lukas@zed.dev>
Co-authored-by: MrSubidubi <finn@zed.dev>
Co-authored-by: Lukas Wirth <me@lukaswirth.dev>
Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>

docs/src/ai/external-agents.md

@@ -196,6 +196,7 @@ You can also add agents through your `settings.json`, by specifying certain fiel
 {
   "agent_servers": {
     "My Custom Agent": {
+      "type": "custom",
       "command": "node",
       "args": ["~/projects/agent/index.js", "--acp"],
       "env": {}

docs/src/configuring-languages.md

@@ -58,6 +58,7 @@ You can customize a wide range of settings for each language, including:
 - [`soft_wrap`](./configuring-zed.md#soft-wrap): How to wrap long lines of code
 - [`show_completions_on_input`](./configuring-zed.md#show-completions-on-input): Whether or not to show completions as you type
 - [`show_completion_documentation`](./configuring-zed.md#show-completion-documentation): Whether to display inline and alongside documentation for items in the completions menu
+- [`colorize_brackets`](./configuring-zed.md#colorize-brackets): Whether to use tree-sitter bracket queries to detect and colorize the brackets in the editor (also known as "rainbow brackets")
 
 These settings allow you to maintain specific coding styles across different languages and projects.
 

docs/src/configuring-zed.md

@@ -4687,6 +4687,18 @@ See the [debugger page](./debugger.md) for more information about debugging supp
 },
 ```
 
+## Colorize Brackets
+
+- Description: Whether to use tree-sitter bracket queries to detect and colorize the brackets in the editor (also known as "rainbow brackets").
+- Setting: `colorize_brackets`
+- Default: `false`
+
+**Options**
+
+`boolean` values
+
+The colors that are used for different indentation levels are defined in the theme (theme key: `accents`). They can be customized by using theme overrides.
+
 ## Unnecessary Code Fade
 
 - Description: How much to fade out unused code.

docs/src/extensions/languages.md

@@ -154,6 +154,14 @@ This query identifies opening and closing brackets, braces, and quotation marks.
 | @open   | Captures opening brackets, braces, and quotes |
 | @close  | Captures closing brackets, braces, and quotes |
 
+Zed uses these to highlight matching brackets: painting each bracket pair with a different color ("rainbow brackets") and highlighting the brackets if the cursor is inside the bracket pair.
+
+To opt out of rainbow brackets colorization, add the following to the corresponding `brackets.scm` entry:
+
+```scheme
+(("\"" @open "\"" @close) (#set! rainbow.exclude))
+```
+
 ### Code outline/structure
 
 The `outline.scm` file defines the structure for the code outline.

docs/src/themes.md

@@ -51,7 +51,15 @@ For example, add the following to your `settings.json` if you wish to override t
         "comment.doc": {
           "font_style": "italic"
         }
-      }
+      },
+      "accents": [
+        "#ff0000",
+        "#ff7f00",
+        "#ffff00",
+        "#00ff00",
+        "#0000ff",
+        "#8b00ff"
+      ]
     }
   }
 }

docs/src/visual-customization.md

@@ -374,6 +374,8 @@ TBD: Centered layout related settings
   "lsp_document_colors": "inlay",        // none, inlay, border, background
   // When to show the scrollbar in the completion menu.
   "completion_menu_scrollbar": "never", // auto, system, always, never
+  // Turn on colorization of brackets in editors (configurable per language)
+  "colorize_brackets": true,
 ```
 
 ### Edit Predictions {#editor-ai}