Merge branch '3428226-cache-empty-menu' into '3.x'

Add menu_link_content_list cache key for menu if empty

See merge request project/twig_tweak!47

src/View/MenuViewBuilder.php

@@ -73,6 +73,7 @@ class MenuViewBuilder {
         '[level]=' . $level,
         '[depth]=' . $depth,
         '[expand]=' . (int) $expand,
+        'menu_link_content_list:' . $menu_name
       ];
     }