Add shortcuts for New Scene and New Inherited Scene actions

These default to Ctrl + N and Ctrl + Shift + N respectively.

editor/editor_node.cpp

@@ -6189,8 +6189,8 @@ EditorNode::EditorNode() {
 
 	p = file_menu->get_popup();
 
-	p->add_shortcut(ED_SHORTCUT("editor/new_scene", TTR("New Scene")), FILE_NEW_SCENE);
-	p->add_shortcut(ED_SHORTCUT("editor/new_inherited_scene", TTR("New Inherited Scene...")), FILE_NEW_INHERITED_SCENE);
+	p->add_shortcut(ED_SHORTCUT("editor/new_scene", TTR("New Scene"), KEY_MASK_CMD + KEY_N), FILE_NEW_SCENE);
+	p->add_shortcut(ED_SHORTCUT("editor/new_inherited_scene", TTR("New Inherited Scene..."), KEY_MASK_CMD + KEY_MASK_SHIFT + KEY_N), FILE_NEW_INHERITED_SCENE);
 	p->add_shortcut(ED_SHORTCUT("editor/open_scene", TTR("Open Scene..."), KEY_MASK_CMD + KEY_O), FILE_OPEN_SCENE);
 	p->add_shortcut(ED_SHORTCUT("editor/reopen_closed_scene", TTR("Reopen Closed Scene"), KEY_MASK_CMD + KEY_MASK_SHIFT + KEY_T), FILE_OPEN_PREV);
 	p->add_submenu_item(TTR("Open Recent"), "RecentScenes", FILE_OPEN_RECENT);