omnipedia_menu.links.action.yml

omnipedia_menu.add_wiki_node_menu_link_form:
  route_name: entity.omnipedia_wiki_node_menu_link.add_link_form
  title: 'Add wiki link'
  # Use the Drupal core menu_ui module's class to add the redirect destination
  # back to the current path, i.e. the menu overview, etc. Thankfully, the class
  # does not restrict what link it's applied to, which is why this works.
  class: \Drupal\menu_ui\Plugin\Menu\LocalAction\MenuLinkAdd
  appears_on:
    - entity.menu.edit_form