Fix issues with extension API that come up when moving Svelte into an extension (#9611)

We're doing it. Svelte support is moving into an extension. This PR
fixes some issues that came up along the way.

Notes

* extensions need to be able to retrieve the path the `node` binary
installed by Zed
* previously we were silently swallowing any errors that occurred while
loading a grammar
* npm commands ran by extensions weren't run in the right directory
* Tree-sitter's WASM stdlib didn't support a C function (`strncmp`)
needed by the Svelte parser's external scanner
* the way that LSP installation status was reported was unnecessarily
complex

Release Notes:

- Removed built-in support for the Svelte and Gleam languages, because
full support for those languages is now available via extensions. These
extensions will be suggested for download when you open a `.svelte` or
`.gleam` file.

---------

Co-authored-by: Marshall <marshall@zed.dev>

crates/copilot/src/copilot.rs

@@ -29,8 +29,7 @@ use std::{
     sync::Arc,
 };
 use util::{
-    async_maybe, fs::remove_matching, github::latest_github_release, http::HttpClient, paths,
-    ResultExt,
+    fs::remove_matching, github::latest_github_release, http::HttpClient, maybe, paths, ResultExt,
 };
 
 actions!(
@@ -1006,7 +1005,7 @@ async fn get_copilot_lsp(http: Arc<dyn HttpClient>) -> anyhow::Result<PathBuf> {
         e @ Err(..) => {
             e.log_err();
             // Fetch a cached binary, if it exists
-            async_maybe!({
+            maybe!(async {
                 let mut last_version_dir = None;
                 let mut entries = fs::read_dir(paths::COPILOT_DIR.as_path()).await?;
                 while let Some(entry) = entries.next().await {