Services changed to Integrations to slack.md

doc/project_services/slack.md

@@ -15,7 +15,7 @@ Slack:
 
 After you set up Slack, it's time to set up GitLab.
 
-Go to your project's **Settings > Services > Slack Notifications** and you will see a
+Go to your project's **Settings > Integrations > Slack Notifications** and you will see a
 checkbox with the following events that can be triggered:
 
 - Push