Merge branch 'docs-support-annotation-template' into 'master'

Add docs for template field in prometheus alerts

See merge request gitlab-org/gitlab-ce!30900

doc/user/project/integrations/prometheus.md

@@ -323,8 +323,9 @@ Once enabled, an issue will be opened automatically when an alert is triggered w
   - `starts_at`: Alert start time via `startsAt`
   - `full_query`: Alert query extracted from `generatorURL`
   - Optional list of attached annotations extracted from `annotations/*`
+- Alert [GFM](../../markdown.md): GitLab Flavored Markdown from `annotations/gitlab_incident_markdown`
 
-To further customize the issue, you can add labels, mentions, or any other supported [quick action](../quick_actions.md) in the selected issue template.
+To further customize the issue, you can add labels, mentions, or any other supported [quick action](../quick_actions.md) in the selected issue template, which will apply to all incidents. To limit quick actions or other information to only specific types of alerts, use the `annotations/gitlab_incident_markdown` field.
 
 Since [version 12.2](https://gitlab.com/gitlab-org/gitlab-ce/issues/63373), GitLab will tag each incident issue with the `incident` label automatically. If the label does not yet exist, it will be created automatically as well.