Fix to category in material.

scene/3d/mesh_instance.cpp

@@ -412,6 +412,7 @@ void MeshInstance::_bind_methods() {
 	ADD_GROUP("Skeleton", "");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "skin", PROPERTY_HINT_RESOURCE_TYPE, "Skin"), "set_skin", "get_skin");
 	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "skeleton", PROPERTY_HINT_NODE_PATH_VALID_TYPES, "Skeleton"), "set_skeleton_path", "get_skeleton_path");
+	ADD_GROUP("", "");
 }
 
 MeshInstance::MeshInstance() {