HackStudio: Greet language servers asynchronously

There's no need to wait for a response after we've sent the project
path to a newly connected language server.

Userland/DevTools/HackStudio/LanguageClient.h

@@ -34,11 +34,11 @@ public:
         : IPC::ServerConnection<LanguageClientEndpoint, LanguageServerEndpoint>(*this, socket)
     {
         m_project_path = project_path;
+        async_greet(m_project_path);
     }
 
     virtual void handshake() override
     {
-        greet(m_project_path);
     }
 
     WeakPtr<LanguageClient> language_client() { return m_current_language_client; }

Userland/DevTools/HackStudio/LanguageServers/LanguageServer.ipc

@@ -1,6 +1,6 @@
 endpoint LanguageServer
 {
-    greet(String project_root) => ()
+    greet(String project_root) =|
 
     file_opened(String filename, IPC::File file) =|
     file_edit_insert_text(String filename, String text, i32 start_line, i32 start_column) =|