update search field docs

Author: kevindees

v6/field-types.md

@@ -461,7 +461,7 @@ For a multi value field,
 $form->search('Links')->multiple();
 ```
 
-! Note, the search field only works for Administrator users because it allows full search access to content using the REST API. You can remove the Administrator-only access limitation by modifying the 'search' middleware group in the HTTP Kernel.
+! Note, the search field only works for Administrator users because it allows full search access to content using the REST API. You can remove the Administrator-only access limitation by modifying the 'search' middleware group in the HTTP Kernel. You can edit your HTTP Kernel at `app/Http/Kernel.php`.
 
 ### Search Post Types