mentions.links.menu.yml

entity.mentions_type.list:
    title: 'Mentions Type'
    parent: system.admin_structure   
    description: 'Manage Mention Types'    
    route_name: entity.mentions_type.list
    
mentions.settings:
  title: Mentions
  route_name: mentions.settings
  parent: system.admin_config_content
  description: Configure Mentions Filter
  weight: 20