svelte: Migrate to tree-sitter-grammars/tree-sitter-svelte (#17529)

> [!NOTE]
> The https://github.com/tree-sitter-grammars/tree-sitter-svelte
repository seems to be more well maintained, with higher quality code,
and as per https://github.com/zed-extensions/svelte/issues/1 it was
suggested that we swap to this repository for Svelte grammars

- Closes https://github.com/zed-industries/zed/issues/17310
- Closes https://github.com/zed-industries/zed/issues/10893
- Closes https://github.com/zed-industries/zed/issues/12833
- Closes https://github.com/zed-extensions/svelte/issues/1
- Closes https://github.com/zed-industries/zed/issues/14943
- Closes https://github.com/zed-extensions/svelte/issues/2

- Added: buffer/file symbol outlines for `.svelte` (`outlines.scm`)
- Improved: Attribute directives & modifiers in `.svelte` files can be
styled independently.
- Fixed: issue where svelte expression inside quotes failed parsing
- Improved: Svelte components in Markup are styled differently from
tags.
- Added: Support for Svelte 5 syntax (`{#snippet children()}`, `{@render
foo()`)
- Change: Svelte now using
[tree-sitter-grammars/tree-sitter-svelte](https://github.com/tree-sitter-grammars/tree-sitter-svelte)
for language highlighting
- Added: Support for typescript syntax in svelte expressions


![image](https://github.com/user-attachments/assets/49d199ee-7550-49a7-912d-070cf691b029)

![image](https://github.com/user-attachments/assets/848ac5b6-62da-4c42-8e24-b7023504f8af)

Release Notes:

- N/A

---

**tree-sitter-grammar things to improve**
- [ ] snippet functions aren't being treated as JS code
- [ ] we should be able to detect @component comments and treat them as
markdown
- [x] `foo:bar` style/class/prop directives
- [x] `--foo="..."` var fields
- [ ] snippet/if blocks's children may need to be indented a little
further

Will implement some of the rest of these in a separate PR

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

docs/src/languages/svelte.md

@@ -2,16 +2,29 @@
 
 Svelte support is available through the [Svelte extension](https://github.com/zed-industries/zed/tree/main/extensions/svelte).
 
-- Tree Sitter: [Himujjal/tree-sitter-svelte](https://github.com/Himujjal/tree-sitter-svelte)
+- Tree Sitter: [tree-sitter-grammars/tree-sitter-svelte](https://github.com/tree-sitter-grammars/tree-sitter-svelte)
 - Language Server: [sveltejs/language-tools](https://github.com/sveltejs/language-tools)
 
-<!--
-TBD: Rewrite Svelte docs so it doesn't begin with a json block assuming you know what inlayHints are.
--->
+## Extra theme styling configuration
+
+You can modify how certain styles such as directives and modifiers appear in attributes:
+
+```json
+"syntax": {
+  // Styling for directives (e.g., `class:foo` or `on:click`) (the `on` or `class` part of the attribute).
+  "attribute.function": {
+    "color": "#ff0000"
+  },
+  // Styling for modifiers at the end of attributes, e.g. `on:<click|preventDefault|stopPropagation>`
+  "attribute.special": {
+    "color": "#00ff00"
+  }
+}
+```
 
 ## Inlay Hints
 
-Zed sets the following initialization options for inlay Hints:
+Zed sets the following initialization options for inlay hints:
 
 ```json
 "inlayHints": {