Rename 'Discard Instancing' to 'Make Local'

Rename the option in the right click menu in the Scene nodes
because Discard Instancing is confusing (it could imply deleting the
instance). I renamed it to Make Local which is used for example in
Blender as well when talking about appending assets from other files.
I think it's clearer. Or it can be renamed to Make Instance Local, but I
thought it's a bit oo long so I went just with Make Local as this option
appears in the menu only when the node is an instance anyway.

editor/scene_tree_dock.cpp

@@ -698,7 +698,7 @@ void SceneTreeDock::_tool_selected(int p_tool, bool p_confirm_override) {
 				}
 			}
 		} break;
-		case TOOL_SCENE_CLEAR_INSTANCING: {
+		case TOOL_SCENE_MAKE_LOCAL: {
 			List<Node *> selection = editor_selection->get_selected_node_list();
 			List<Node *>::Element *e = selection.front();
 			if (e) {
@@ -710,7 +710,7 @@ void SceneTreeDock::_tool_selected(int p_tool, bool p_confirm_override) {
 						break;
 
 					ERR_FAIL_COND(node->get_filename() == String());
-					undo_redo->create_action(TTR("Discard Instancing"));
+					undo_redo->create_action(TTR("Make Local"));
 					undo_redo->add_do_method(node, "set_filename", "");
 					undo_redo->add_undo_method(node, "set_filename", node->get_filename());
 					_node_replace_owner(node, node, root);
@@ -1923,7 +1923,7 @@ void SceneTreeDock::_tree_rmb(const Vector2 &p_menu_pos) {
 				bool placeholder = selection[0]->get_scene_instance_load_placeholder();
 				menu->add_check_item(TTR("Editable Children"), TOOL_SCENE_EDITABLE_CHILDREN);
 				menu->add_check_item(TTR("Load As Placeholder"), TOOL_SCENE_USE_PLACEHOLDER);
-				menu->add_item(TTR("Discard Instancing"), TOOL_SCENE_CLEAR_INSTANCING);
+				menu->add_item(TTR("Make Local"), TOOL_SCENE_MAKE_LOCAL);
 				menu->add_icon_item(get_icon("Load", "EditorIcons"), TTR("Open in Editor"), TOOL_SCENE_OPEN);
 				menu->set_item_checked(menu->get_item_idx_from_text(TTR("Editable Children")), editable);
 				menu->set_item_checked(menu->get_item_idx_from_text(TTR("Load As Placeholder")), placeholder);

editor/scene_tree_dock.h

@@ -76,7 +76,7 @@ class SceneTreeDock : public VBoxContainer {
 		TOOL_BUTTON_MAX,
 		TOOL_SCENE_EDITABLE_CHILDREN,
 		TOOL_SCENE_USE_PLACEHOLDER,
-		TOOL_SCENE_CLEAR_INSTANCING,
+		TOOL_SCENE_MAKE_LOCAL,
 		TOOL_SCENE_OPEN,
 		TOOL_SCENE_CLEAR_INHERITANCE,
 		TOOL_SCENE_CLEAR_INHERITANCE_CONFIRM,