Instruct users to restart application after change

doc/administration/user_settings.md

 ---
-stage: Enablement
-group: Distribution
+stage: Manage
+group: Access
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
@@ -10,7 +10,8 @@ GitLab administrators can modify user settings for the entire GitLab instance.
 
 ## Disallow users creating top-level groups
 
-By default, new users can create top-level groups. To disable this, modify the appropriate configuration file.
+By default, new users can create top-level groups. To disable this, modify the appropriate configuration file,
+and then [reconfigure and restart GitLab](restart_gitlab.md).
 
 For Omnibus installations, add the following to `/etc/gitlab/gitlab.rb`:
 
@@ -26,7 +27,8 @@ For source installations, uncomment the following line in `config/gitlab.yml`:
 
 ## Disallow users changing usernames
 
-By default, new users can change their usernames. To disable this, modify the appropriate configuration file.
+By default, new users can change their usernames. To disable this, modify the appropriate configuration file,
+and then [reconfigure and restart GitLab](restart_gitlab.md).
 
 For Omnibus installations, add the following to `/etc/gitlab/gitlab.rb`: