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/language/src/language.rs

@@ -134,11 +134,15 @@ pub struct CachedLspAdapter {
     pub language_ids: HashMap<String, String>,
     pub adapter: Arc<dyn LspAdapter>,
     pub reinstall_attempt_count: AtomicU64,
+    /// Indicates whether this language server is the primary language server
+    /// for a given language. Currently, most LSP-backed features only work
+    /// with one language server, so one server needs to be primary.
+    pub is_primary: bool,
     cached_binary: futures::lock::Mutex<Option<LanguageServerBinary>>,
 }
 
 impl CachedLspAdapter {
-    pub fn new(adapter: Arc<dyn LspAdapter>) -> Arc<Self> {
+    pub fn new(adapter: Arc<dyn LspAdapter>, is_primary: bool) -> Arc<Self> {
         let name = adapter.name();
         let disk_based_diagnostic_sources = adapter.disk_based_diagnostic_sources();
         let disk_based_diagnostics_progress_token = adapter.disk_based_diagnostics_progress_token();
@@ -150,6 +154,7 @@ impl CachedLspAdapter {
             disk_based_diagnostics_progress_token,
             language_ids,
             adapter,
+            is_primary,
             cached_binary: Default::default(),
             reinstall_attempt_count: AtomicU64::new(0),
         })
@@ -293,7 +298,6 @@ pub trait LspAdapter: 'static + Send + Sync {
                     .cached_server_binary(container_dir.to_path_buf(), delegate.as_ref())
                     .await
                 {
-                    delegate.update_status(self.name(), LanguageServerBinaryStatus::Cached);
                     log::info!(
                         "failed to fetch newest version of language server {:?}. falling back to using {:?}",
                         self.name(),
@@ -464,7 +468,7 @@ async fn try_fetch_server_binary<L: LspAdapter + 'static + Send + Sync + ?Sized>
         .fetch_server_binary(latest_version, container_dir, delegate.as_ref())
         .await;
 
-    delegate.update_status(name.clone(), LanguageServerBinaryStatus::Downloaded);
+    delegate.update_status(name.clone(), LanguageServerBinaryStatus::None);
     binary
 }