Adding a new separate menu link to /admin/config in page? Adding new separate menu link in admin config page  like development service
Adding link to admin config under development, media, service is easy but creating new separate menu like admin_config_development, admin_config_service , admin_config_media is bit tricky. 

As mentioned in


  Create same file with small alteration  modulename.links.menu.yml

modulename.admin_config_modulename:
  title: ' settings'
  description: ' selection.'
  route_name: modulename.settings
  parent: 'system.admin_config'
modulename.second_link:
  title: 'settings'
  description: 'selection.'
  route_name: modulename.settinganother
  parent: 'modulename.admin_config_modulename'  
  menu_name: modulename

  
  By: monkpal