Stop extensions' servers and message loops before removing their files (#34208)

Fixes an issue that caused Windows to fail when removing extension's
directories, as Zed had never stop any related processes.

Now:

* Zed shuts down and waits until the end when the language servers are
shut down

* Adds `impl Drop for WasmExtension` where does
`self.tx.close_channel();` to stop a receiver loop that holds the "lock"
on the extension's work dir.
The extension was dropped, but the channel was not closed for some
reason.

* Does more unregistration to ensure `Arc<WasmExtension>` with the `tx`
does not leak further

* Tidies up the related errors which had never reported a problematic
path before

Release Notes:

- N/A

---------

Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>
Co-authored-by: Smit <smit@zed.dev>

crates/language_extension/src/language_extension.rs

@@ -5,13 +5,26 @@ use std::sync::Arc;
 
 use anyhow::Result;
 use extension::{ExtensionGrammarProxy, ExtensionHostProxy, ExtensionLanguageProxy};
+use gpui::{App, Entity};
 use language::{LanguageMatcher, LanguageName, LanguageRegistry, LoadedLanguage};
+use project::LspStore;
+
+#[derive(Clone)]
+pub enum LspAccess {
+    ViaLspStore(Entity<LspStore>),
+    ViaWorkspaces(Arc<dyn Fn(&mut App) -> Result<Vec<Entity<LspStore>>> + Send + Sync + 'static>),
+    Noop,
+}
 
 pub fn init(
+    lsp_access: LspAccess,
     extension_host_proxy: Arc<ExtensionHostProxy>,
     language_registry: Arc<LanguageRegistry>,
 ) {
-    let language_server_registry_proxy = LanguageServerRegistryProxy { language_registry };
+    let language_server_registry_proxy = LanguageServerRegistryProxy {
+        language_registry,
+        lsp_access,
+    };
     extension_host_proxy.register_grammar_proxy(language_server_registry_proxy.clone());
     extension_host_proxy.register_language_proxy(language_server_registry_proxy.clone());
     extension_host_proxy.register_language_server_proxy(language_server_registry_proxy);
@@ -20,6 +33,7 @@ pub fn init(
 #[derive(Clone)]
 struct LanguageServerRegistryProxy {
     language_registry: Arc<LanguageRegistry>,
+    lsp_access: LspAccess,
 }
 
 impl ExtensionGrammarProxy for LanguageServerRegistryProxy {