Docs: Move alert rule section to alerting fundamentals section (#49657)

* initial commit

* Added links to alert rules, and fixes one broken alerting relref.

docs/sources/alerting/_index.md

@@ -22,6 +22,7 @@ Existing installations that upgrade to v9.0 will have Grafana alerting enabled b
 
 Before you begin, we recommend that you familiarize yourself with some of the [fundamental concepts]({{< relref "./fundamentals/_index.md" >}}) of Grafana alerting. Refer to [Role-based access control]({{< relref "../enterprise/access-control/_index.md" >}}) in Grafana Enterprise to learn more about controlling access to alerts using role-based permissions.
 
+- [About alert rules]({{< relref "./fundamentals/alert-rules/_index.md" >}})
 - [Migrating legacy alerts]({{< relref "./migrating-alerts/_index.md" >}})
 - [Disable Grafana alerting in OSS]({{< relref "./migrating-alerts/opt-out.md" >}})
 - [Create Grafana managed alerting rules]({{< relref "alerting-rules/create-grafana-managed-rule.md" >}})

docs/sources/alerting/fundamentals/_index.md

@@ -8,6 +8,7 @@ weight = 110
 
 This section includes the following fundamental concepts of Grafana alerting:
 
+- [Alert rules]({{< relref "./alert-rules/_index.md" >}})
 - [Annotations and labels for alerting rules]({{< relref "./annotation-label/_index.md" >}})
 - [Alertmanager]({{< relref "./alertmanager.md" >}})
 - [State and health of alerting rules]({{< relref "./state-and-health.md" >}})

docs/sources/alerting/fundamentals/alert-rules/_index.md

@@ -1,6 +1,6 @@
 +++
-title = "About alert rules"
-description = "Learn about Grafana alert rules"
+title = "Alert rules"
+description = "About Grafana alert rules"
 keywords = ["grafana", "alerting", "rules"]
 weight = 101
 +++
@@ -16,4 +16,4 @@ An interval specifies how frequently an alerting rule is evaluated. Duration, wh
 - [Alert rule types]({{< relref "./alert-rule-types.md" >}})
 - [Alert instances]({{< relref "./alert-instances.md" >}})
 - [Organising alert rules]({{< relref "./organising-alerts.md" >}})
-- [Annotation and labels]({{< relref "../fundamentals/annotation-label/_index.md" >}})
+- [Annotation and labels]({{< relref "../annotation-label/_index.md" >}})

docs/sources/alerting/migrating-alerts/opt-out.md

@@ -30,7 +30,7 @@ To opt-out of Grafana alerts and roll back to legacy dashboard alerting:
 
 When you are ready to make the switch, the following procedure will help you migrate to Grafana alerting.
 
-To opt-in Grafana alerts:
+To opt-in to Grafana alerts:
 
 1. In your custom configuration file ($WORKING_DIR/conf/custom.ini), go to the [unified alerts]({{< relref "../../administration/configuration.md#unified_alerting" >}}) section.
 1. Set the `enabled` property to `true`.