Line wraps, spelling, minor wording fixes

A few things to bring the page closer to GitLab style.

doc/operations/incident_management/alert_notifications.md

@@ -4,29 +4,30 @@ group: Health
 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/#designated-technical-writers
 ---
 
-# Alert notifications
+# Paging and notifications
 
-GitLab can react to alerts triggered from your applications. When an alert is
-triggered in GitLab by [managed-Prometheus](../../user/project/integrations/prometheus.md#managed-prometheus-on-kubernetes)
-or triggered using an external source and received with an integration, it's
-important for a responder to be notified.
-
-Responders can receive notifications using the methods described on this page.
+When there is a new alert or incident, it is important for a responder to be notified
+immediately so they can triage and respond to the problem. Responders can receive
+notifications using the methods described on this page.
 
 ## Slack notifications
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/216326) in GitLab 13.1.
 
-You can be alerted by a Slack message when a new alert has been triggered.
-
-For setup information, see the [Slack Notifications Service docs](../../user/project/integrations/slack.md).
+Responders can be paged via Slack using the
+[Slack Notifications Service](../../user/project/integrations/slack.md), which you
+can configure for new alerts and new incidents. After configuring, responders
+receive a **single** page via Slack. To set up Slack notifications on your mobile
+device, make sure to enable notifications for the Slack app on your phone so
+you never miss a page.
 
 ## Email notifications
 
-If a project has been [configured to create incidents for triggered alerts](incidents.md#configure-incidents),
-projects members with the _Owner_ or _Maintainer_ role will be sent an email
-notification. To send additional email notifications to project members with the
-Developer role:
+Email notifications are available in projects that have been
+[configured to create incidents automatically](incidents.md#configure-incidents)
+for triggered alerts. Project members with the **Owner** or **Maintainer** roles are
+sent an email notification automatically. (This is not configurable.) To optionally
+send additional email notifications to project members with the **Developer** role:
 
 1. Navigate to **Settings > Operations**.
 1. Expand the **Incidents** section.