docs: Update language docs and include links in the sidebar (#13828)

This PR updates the supported language docs and adds them to the sidebar
for better discoverability.

Release Notes:

- N/A

docs/src/languages/vue.md

@@ -1,6 +1,5 @@
 # Vue
 
-- Tree Sitter: [tree-sitter-vue](https://github.com/zed-industries/tree-sitter-vue)
-- Language Server: [@vue/language-server](https://github.com/vuejs/language-tools/tree/master/packages/language-server)
+Vue support is available through the [Vue extension](https://github.com/zed-industries/zed/tree/main/extensions/vue).
 
-> Pinned `@vue/language-server` to version 1.8 until Zed supports 2.x #9846
+> `@vue/language-server` is pinned to v1.8 due to some issues in v2.x [#9846](https://github.com/zed-industries/zed/pull/9846)