Alerting docs: Add one notification template example that prints a title or subject (#95680)

docs/sources/alerting/configure-notifications/template-notifications/examples.md

@@ -50,6 +50,11 @@ refs:
       destination: /docs/grafana/<GRAFANA_VERSION>/alerting/configure-notifications/template-notifications/language/
     - pattern: /docs/grafana-cloud/
       destination: /docs/grafana-cloud/alerting-and-irm/alerting/configure-notifications/template-notifications/language/
+  group-alert-notifications:
+    - pattern: /docs/grafana/
+      destination: /docs/grafana/<GRAFANA_VERSION>/alerting/fundamentals/notifications/group-alert-notifications/
+    - pattern: /docs/grafana-cloud/
+      destination: /docs/grafana-cloud/alerting-and-irm/alerting/fundamentals/notifications/group-alert-notifications/
 ---
 
 # Notification template examples
@@ -321,3 +326,37 @@ The output of this template looks like this:
 - Silence: https://example.com/alerting/silence/new
 - RunbookURL: https://example.com/on-call/web_server_http_errors
 ```
+
+## Print a notification title or subject
+
+A title or subject provides a one-line summary of the notification content.
+
+Here’s a basic example that displays the number of firing and resolved alerts in the notification.
+
+```go
+{{ define "custom_title" -}}
+{{ if gt (.Alerts.Firing | len) 0 }}🚨 {{ .Alerts.Firing | len }} firing alerts. {{ end }}{{ if gt (.Alerts.Resolved | len) 0 }}✅ {{ .Alerts.Resolved | len }} resolved alerts.{{ end }}
+{{ end -}}
+```
+
+```template_output
+🚨 1 firing alerts. ✅ 1 resolved alerts.
+```
+
+The next example is a copy of the default title/subject template used in Grafana.
+
+```go
+{{ define "copy_of_default_title" -}}
+[{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ if gt (.Alerts.Resolved | len) 0 }}, RESOLVED:{{ .Alerts.Resolved | len }}{{ end }}{{ end }}] {{ .GroupLabels.SortedPairs.Values | join " " }} {{ if gt (len .CommonLabels) (len .GroupLabels) }}({{ with .CommonLabels.Remove .GroupLabels.Names }}{{ .Values | join " " }}{{ end }}){{ end }}
+{{ end }}
+```
+
+This is a more advanced example:
+
+- Prints the number of firing and resolved alerts in the notification.
+- Outputs `.GroupLabels`, the labels used to [group multiple alerts in one notification](ref:group-alert-notifications).
+- Prints `CommonLabels`, excluding labels in `.GroupLabels`.
+
+```template_output
+[FIRING:1, RESOLVED:1] api warning (sql_db)
+```