Add initial support for defining language server adapters in WebAssembly-based extensions (#8645)

This PR adds **internal** ability to run arbitrary language servers via
WebAssembly extensions. The functionality isn't exposed yet - we're just
landing this in this early state because there have been a lot of
changes to the `LspAdapter` trait, and other language server logic.

## Next steps

* Currently, wasm extensions can only define how to *install* and run a
language server, they can't yet implement the other LSP adapter methods,
such as formatting completion labels and workspace symbols.
* We don't have an automatic way to install or develop these types of
extensions
* We don't have a way to package these types of extensions in our
extensions repo, to make them available via our extensions API.
* The Rust extension API crate, `zed-extension-api` has not yet been
published to crates.io, because we still consider the API a work in
progress.

Release Notes:

- N/A

---------

Co-authored-by: Marshall <marshall@zed.dev>
Co-authored-by: Nathan <nathan@zed.dev>
Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

crates/languages/src/lib.rs

@@ -122,15 +122,17 @@ pub fn init(
         ("dart", tree_sitter_dart::language()),
     ]);
 
-    let language = |asset_dir_name: &'static str, adapters| {
+    let language = |asset_dir_name: &'static str, adapters: Vec<Arc<dyn LspAdapter>>| {
         let config = load_config(asset_dir_name);
+        for adapter in adapters {
+            languages.register_lsp_adapter(config.name.clone(), adapter);
+        }
         languages.register_language(
             config.name.clone(),
             config.grammar.clone(),
             config.matcher.clone(),
-            adapters,
             move || Ok((config.clone(), load_queries(asset_dir_name))),
-        )
+        );
     };
 
     language(
@@ -329,15 +331,9 @@ pub fn init(
 }
 
 #[cfg(any(test, feature = "test-support"))]
-pub async fn language(
-    name: &str,
-    grammar: tree_sitter::Language,
-    lsp_adapter: Option<Arc<dyn LspAdapter>>,
-) -> Arc<Language> {
+pub fn language(name: &str, grammar: tree_sitter::Language) -> Arc<Language> {
     Arc::new(
         Language::new(load_config(name), Some(grammar))
-            .with_lsp_adapters(lsp_adapter.into_iter().collect())
-            .await
             .with_queries(load_queries(name))
             .unwrap(),
     )