[3.x] Add Editor Description group

Backport from 4.0

scene/main/node.cpp

@@ -3081,6 +3081,7 @@ void Node::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("_set_editor_description", "editor_description"), &Node::set_editor_description);
 	ClassDB::bind_method(D_METHOD("_get_editor_description"), &Node::get_editor_description);
+	ADD_GROUP("Editor Description", "editor_");
 	ADD_PROPERTY(PropertyInfo(Variant::STRING, "editor_description", PROPERTY_HINT_MULTILINE_TEXT, "", PROPERTY_USAGE_EDITOR | PROPERTY_USAGE_INTERNAL), "_set_editor_description", "_get_editor_description");
 
 	ClassDB::bind_method(D_METHOD("_set_import_path", "import_path"), &Node::set_import_path);