Fix editor needs restart after adding GDExtensions

editor/editor_node.cpp

@@ -481,6 +481,9 @@ void EditorNode::_gdextensions_reloaded() {
 	// In case the developer is inspecting an object that will be changed by the reload.
 	InspectorDock::get_inspector_singleton()->update_tree();
 
+	// Reload script editor to revalidate GDScript if classes are added or removed.
+	ScriptEditor::get_singleton()->reload_scripts(true);
+
 	// Regenerate documentation.
 	EditorHelp::generate_doc();
 }