Update HA monitoring architecture doc

• Updates documentation for HA in Prometheus, AlertManager, and Grafana

• Closes monitoring#81

docs/understanding-bigbang/package-architecture/monitoring.md

@@ -199,18 +199,12 @@ Note: Other packages are responsible for deploying Service Monitors for their co
 ### HA
 
 High Availability can be accomplished by increasing the number of replicas for the deployments of Alertmanager, Prometheus and Grafana:
-
 ```yaml
 monitoring:
   values:
     alertmanager:
       alertmanagerSpec:
-        replicas:
-    prometheus:
-      prometheusSpec:
-        replicas:
-    grafana:
-      replicas:
+        replicas: 3
 ```
 
 ### Dependency Packages