Docs: Add step for custom labels in alert form (#59027)

docs/sources/alerting/alerting-rules/create-grafana-managed-rule.md

@@ -43,7 +43,8 @@ Watch this video to learn more about creating alerts: {{< vimeo 720001934 >}}
    - For **Group**, specify a pre-defined group. Newly created rules are appended to the end of the group. Rules within a group are run sequentially at a regular interval, with the same evaluation time.
    - Add a description and summary to customize alert messages. Use the guidelines in [Annotations and labels for alerting]({{< relref "../fundamentals/annotation-label/" >}}).
    - Add Runbook URL, panel, dashboard, and alert IDs.
-   - Add custom labels.
+1. In Step 5, add custom labels.
+   - Add custom labels selecting existing key-value pairs from the drop down, or add new labels by entering the new key or value .
 1. Click **Save** to save the rule or **Save and exit** to save the rule and go back to the Alerting page.
 1. Next, create a for the rule.
 

docs/sources/alerting/alerting-rules/create-mimir-loki-managed-recording-rule.md

@@ -67,5 +67,6 @@ To create a Grafana Mimir or Loki managed recording rule
 1. In Step 4, add additional metadata associated with the rule.
    - Add a description and summary to customize alert messages. Use the guidelines in [Annotations and labels for alerting]({{< relref "../fundamentals/annotation-label/" >}}).
    - Add Runbook URL, panel, dashboard, and alert IDs.
-   - Add custom labels.
+1. In Step 5, add custom labels.
+   - Add custom labels selecting existing key-value pairs from the drop down, or add new labels by entering the new key or value .
 1. Click **Save** to save the rule or **Save and exit** to save the rule and go back to the Alerting page.

docs/sources/alerting/alerting-rules/create-mimir-loki-managed-rule.md

@@ -50,6 +50,7 @@ Watch this video to learn more about how to create a Mimir managed alert rule: {
    - From the **Group** drop-down, select an existing group within the selected namespace. Otherwise, click **Add new** and enter a name to create a new one. Newly created rules are appended to the end of the group. Rules within a group are run sequentially at a regular interval, with the same evaluation time.
    - Add a description and summary to customize alert messages. Use the guidelines in [Annotations and labels for alerting]({{< relref "../fundamentals/annotation-label/" >}}).
    - Add Runbook URL, panel, dashboard, and alert IDs.
-   - Add custom labels.
+1. In Step 5, add custom labels.
+   - Add custom labels selecting existing key-value pairs from the drop down, or add new labels by entering the new key or value .
 1. Click **Save** to save the rule or **Save and exit** to save the rule and go back to the Alerting page.
 1. Next, create a notification for the rule.