Add metric to Auto DevOps dev guide

doc/administration/monitoring/prometheus/gitlab_metrics.md

@@ -83,6 +83,7 @@ The following metrics are available:
 | `upload_file_does_not_exist`                                   | Counter   | 10.7 in EE, 11.5 in CE | Number of times an upload record could not find its file                                            |                                                     |
 | `failed_login_captcha_total`                                   | Gauge     |                   11.0 | Counter of failed CAPTCHA attempts during login                                                     |                                                     |
 | `successful_login_captcha_total`                               | Gauge     |                   11.0 | Counter of successful CAPTCHA attempts during login                                                 |                                                     |
+| `auto_devops_pipelines_completed_total`                        | Counter   |                   12.7 | Counter of completed Auto DevOps pipelines, labeled by status                                       |                                                     |
 
 ## Metrics controlled by a feature flag
 

doc/development/auto_devops.md

@@ -40,3 +40,10 @@ found in
 
 Configuring [GDK for Auto
 DevOps](https://gitlab.com/gitlab-org/gitlab-development-kit/blob/master/doc/howto/auto_devops.md).
+
+## Monitoring on GitLab.com
+
+The metric
+[`auto_devops_completed_pipelines_total`](https://thanos-query.ops.gitlab.net/graph?g0.range_input=72h&g0.max_source_resolution=0s&g0.expr=sum(increase(auto_devops_pipelines_completed_total%7Benvironment%3D%22gprd%22%7D%5B60m%5D))%20by%20(status)&g0.tab=0)
+(only available to GitLab team members) counts completed Auto DevOps
+pipelines, labeled by status.