"Cluster is missing an active mongos" alert is possibly misleading

Description

In the alerts documentation:

• https://docs.cloudmanager.mongodb.com/reference/alerts/#sharded-cluster-alerts
• https://docs.opsmanager.mongodb.com/current/reference/alerts/#sharded-cluster-alerts

For the condition "Cluster is missing an active mongos", it says the alert trigger is "Ops Manager cannot reach a mongos for the cluster." At least one customer was misled into believe that to mean they would be alerted if a mongos router wasn't running. In fact, that alert will only fire if *all* mongoesses are down.

Please if possible change the alert trigger description to

Ops Manager cannot reach any of the mongos for the cluster.

Scope of changes

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)