Remove duplicate alert notification section

doc/operations/incident_management/index.md

@@ -16,27 +16,6 @@ GitLab offers solutions for handling incidents in your applications and services
 such as [setting up Prometheus alerts](#configure-prometheus-alerts),
 [displaying metrics](./alert_details.md#embed-metrics-in-incidents-and-issues), and sending notifications.
 
-## Alert notifications
-
-### Slack Notifications
-
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/216326) in GitLab 13.1.
-
-You can be alerted via a Slack message when a new alert has been received.
-
-See the [Slack Notifications Service docs](../../user/project/integrations/slack.md) for information on how to set this up.
-
-### Notify developers of alerts
-
-GitLab can react to the alerts triggered from your applications and services
-by creating issues and alerting developers through email. By default, GitLab
-sends these emails to [owners and maintainers](../../user/permissions.md) of the project.
-These emails contain details of the alert, and a link for more information.
-
-To send separate email notifications to users with
-[Developer permissions](../../user/permissions.md), see
-[Configure incidents](./incidents.md#configure-incidents).
-
 ## Configure Prometheus alerts
 
 You can set up Prometheus alerts in: