Issue #3424560 - Add permission

mpac.permissions.yml

+manage mpac settings:
+  title: 'Manage multi-path autocomplete settings'
+  description: 'Allows a user to manage multi-path autocomplete settings.'

mpac.routing.yml

@@ -10,4 +10,4 @@ mpac.autocomplete_settings:
   defaults:
     _form: '\Drupal\mpac\Form\AutocompleteSettingsForm'
   requirements:
-    _permission: 'administer site configuration'
+    _permission: 'manage mpac settings'