Register the DisplayServer Singleton

servers/register_server_types.cpp

@@ -216,6 +216,7 @@ void unregister_server_types() {
 
 void register_server_singletons() {
 
+	Engine::get_singleton()->add_singleton(Engine::Singleton("DisplayServer", DisplayServer::get_singleton()));
 	Engine::get_singleton()->add_singleton(Engine::Singleton("RenderingServer", RenderingServer::get_singleton()));
 	Engine::get_singleton()->add_singleton(Engine::Singleton("AudioServer", AudioServer::get_singleton()));
 	Engine::get_singleton()->add_singleton(Engine::Singleton("PhysicsServer2D", PhysicsServer2D::get_singleton()));