racket: Extract to zed-extensions/racket repository (#22630)

This PR extracts the Racket extension to the
[zed-extensions/racket](https://github.com/zed-extensions/racket)
repository.

Release Notes:

- N/A

extensions/racket/LICENSE-APACHE

@@ -1 +0,0 @@
-../../LICENSE-APACHE

extensions/racket/extension.toml

@@ -1,11 +0,0 @@
-id = "racket"
-name = "Racket"
-description = "Racket support."
-version = "0.0.2"
-schema_version = 1
-authors = ["Mikayla Maki <mikayla@zed.dev>"]
-repository = "https://github.com/zed-industries/zed"
-
-[grammars.racket]
-repository = "https://github.com/zed-industries/tree-sitter-racket"
-commit = "beb29de2b668110e69df0c6d51649c3e2c91d863"

extensions/racket/languages/racket/brackets.scm

@@ -1,3 +0,0 @@
-("(" @open ")" @close)
-("[" @open "]" @close)
-("{" @open "}" @close)

extensions/racket/languages/racket/config.toml

@@ -1,10 +0,0 @@
-name = "Racket"
-grammar = "racket"
-path_suffixes = ["rkt"]
-line_comments = ["; "]
-autoclose_before = "])"
-brackets = [
-    { start = "[", end = "]", close = true, newline = false },
-    { start = "(", end = ")", close = true, newline = false },
-    { start = "\"", end = "\"", close = true, newline = false },
-]

extensions/racket/languages/racket/indents.scm

@@ -1,3 +0,0 @@
-(_ "[" "]") @indent
-(_ "{" "}") @indent
-(_ "(" ")") @indent

extensions/racket/languages/racket/outline.scm

@@ -1,10 +0,0 @@
-(list
-    .
-    (symbol) @start-symbol @context
-    .
-    [
-        (symbol) @name
-        (list . (symbol) @name)
-    ]
-    (#match? @start-symbol "^define")
-) @item