RHIDP-5421 - Document which plugins in RHDH have metrics

Author: Gerry-Forde

artifacts/rhdh-plugins-reference/keycloak/keycloak-plugin-admin.adoc

@@ -160,13 +160,24 @@ The Keycloak backend plugin supports link:https://opentelemetry.io/[OpenTelemetr
 
 === Labels
 
-All counters include the `taskInstanceId` label, which uniquely identifies each scheduled fetch task. You can use this label to trace failures back to individual task executions. For example:
+All counters include the `taskInstanceId` label, which uniquely identifies each scheduled fetch task. You can use this label to trace failures back to individual task executions. 
+
+Users can enter queries in the Prometheus UI or Grafana to explore and manipulate metric data. 
+
+In the following example, the Prometheus Query Language (PromQL) expression returns the number of backend failures associated with a `taskInstanceId`:
 
 [source,subs="+attributes,+quotes"]
 ----
 backend_keycloak_fetch_data_batch_failure_count_total{taskInstanceId="df040f82-2e80-44bd-83b0-06a984ca05ba"} 1
 ----
 
+[NOTE]
+====
+PromQL supports arithmetic operations, comparison operators, logical/set operations, aggregation, and various functions. Users can combine these features to analyze time-series data effectively.
+
+Additionally, the results can be visualized using Grafana.
+====
+
 // === Use Case Example
 
 // Imagine your Keycloak instance is under-provisioned (e.g., low CPU/RAM limits), and the plugin is configured to send many parallel API requests.