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/util/src/util.rs

@@ -426,21 +426,20 @@ pub fn unzip_option<T, U>(option: Option<(T, U)>) -> (Option<T>, Option<U>) {
     }
 }
 
-/// Evaluates to an immediately invoked function expression. Good for using the ? operator
-/// in functions which do not return an Option or Result
+/// Expands to an immediately-invoked function expression. Good for using the ? operator
+/// in functions which do not return an Option or Result.
+///
+/// Accepts a normal block, an async block, or an async move block.
 #[macro_export]
 macro_rules! maybe {
     ($block:block) => {
         (|| $block)()
     };
-}
-
-/// Evaluates to an immediately invoked function expression. Good for using the ? operator
-/// in functions which do not return an Option or Result, but async.
-#[macro_export]
-macro_rules! async_maybe {
-    ($block:block) => {
-        (|| async move { $block })()
+    (async $block:block) => {
+        (|| async $block)()
+    };
+    (async move $block:block) => {
+        (|| async move $block)()
     };
 }