Correlations: change casing of *UID properties (#52836)

* Correlations: change casing of *UID properties

* add link to correlations HTTP API

docs/sources/developers/http_api/_index.md

@@ -25,6 +25,7 @@ dashboards, creating users, and updating data sources.
 - [Alerting Provisioning API]({{< relref "alerting_provisioning/" >}})
 - [Annotations API]({{< relref "annotations/" >}})
 - [Authentication API]({{< relref "auth/" >}})
+- [Correlations API]({{< relref "correlations/" >}})
 - [Dashboard API]({{< relref "dashboard/" >}})
 - [Dashboard Permissions API]({{< relref "dashboard_permissions/" >}})
 - [Dashboard Versions API]({{< relref "dashboard_versions/" >}})