Extract PureScript support into an extension (#9824)

This PR extracts PureScript support into an extension and removes the
built-in PureScript support from Zed.

Release Notes:

- Removed built-in support for PureScript, in favor of making it
available as an extension. The PureScript extension will be suggested
for download when you open a `.purs` file.

Cargo.lock

@@ -5322,7 +5322,6 @@ dependencies = [
  "tree-sitter-ocaml",
  "tree-sitter-php",
  "tree-sitter-proto",
- "tree-sitter-purescript",
  "tree-sitter-python",
  "tree-sitter-racket",
  "tree-sitter-regex",
@@ -10412,15 +10411,6 @@ dependencies = [
  "tree-sitter",
 ]
 
-[[package]]
-name = "tree-sitter-purescript"
-version = "0.1.0"
-source = "git+https://github.com/postsolar/tree-sitter-purescript?rev=v0.1.0#0554811a512b9cec08b5a83ce9096eb22da18213"
-dependencies = [
- "cc",
- "tree-sitter",
-]
-
 [[package]]
 name = "tree-sitter-python"
 version = "0.20.4"
@@ -12613,6 +12603,13 @@ dependencies = [
  "zed_extension_api 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "zed_purescript"
+version = "0.0.1"
+dependencies = [
+ "zed_extension_api 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "zed_svelte"
 version = "0.0.1"