Properly register buffers with reused language servers (#32057)

Follow-up of https://github.com/zed-industries/zed/pull/30707

The old code does something odd, re-accessing essentially the same
adapter-server pair for every language server initialized; but that was
done before for "incorrect", non-reused worktree_id hence never resulted
in external worktrees' files registration in this code path.

Release Notes:

- Fixed certain external worktrees' files sometimes not registered with
language servers

crates/project/src/lsp_store.rs

@@ -2308,7 +2308,7 @@ impl LocalLspStore {
                     });
                 (false, lsp_delegate, servers)
             });
-        let servers = servers
+        let servers_and_adapters = servers
             .into_iter()
             .filter_map(|server_node| {
                 if reused && server_node.server_id().is_none() {
@@ -2384,14 +2384,14 @@ impl LocalLspStore {
                     },
                 )?;
                 let server_state = self.language_servers.get(&server_id)?;
-                if let LanguageServerState::Running { server, .. } = server_state {
+                if let LanguageServerState::Running { server, adapter, .. } = server_state {
-                    Some(server.clone())
+                    Some((server.clone(), adapter.clone()))
                 } else {
                     None
                 }
             })
             .collect::<Vec<_>>();
-        for server in servers {
+        for (server, adapter) in servers_and_adapters {
             buffer_handle.update(cx, |buffer, cx| {
                 buffer.set_completion_triggers(
                     server.server_id(),
@@ -2409,32 +2409,12 @@ impl LocalLspStore {
                     cx,
                 );
             });
-        }
-        for adapter in self.languages.lsp_adapters(&language.name()) {
-            let servers = self
-                .language_server_ids
-                .get(&(worktree_id, adapter.name.clone()))
-                .map(|ids| {
-                    ids.iter().flat_map(|id| {
-                        self.language_servers.get(id).and_then(|server_state| {
-                            if let LanguageServerState::Running { server, .. } = server_state {
-                                Some(server.clone())
-                            } else {
-                                None
-                            }
-                        })
-                    })
-                });
-            let servers = match servers {
-                Some(server) => server,
-                None => continue,
-            };
 
-            for server in servers {
             let snapshot = LspBufferSnapshot {
                 version: 0,
                 snapshot: initial_snapshot.clone(),
             };
+
             self.buffer_snapshots
                 .entry(buffer_id)
                 .or_default()
@@ -2451,7 +2431,6 @@ impl LocalLspStore {
                 });
         }
     }
-    }
 
     fn reuse_existing_language_server(
         &self,