Add summary to Alertmanager rules where missing - updated accoring to guidelines

assets/prometheus/rules/alertmanager.rules.yaml

@@ -11,6 +11,7 @@ groups:
     annotations:
       description: The configuration of the instances of the Alertmanager cluster
         `{{$labels.service}}` are out of sync.
+      summary: Configuration out of sync
   - alert: AlertmanagerDownOrMissing
     expr: label_replace(prometheus_operator_alertmanager_spec_replicas, "job", "alertmanager-$1",
       "alertmanager", "(.*)") / ON(job) GROUP_RIGHT() sum(up) BY (job) != 1
@@ -20,6 +21,7 @@ groups:
     annotations:
       description: An unexpected number of Alertmanagers are scraped or Alertmanagers
         disappeared from discovery.
+      summary: Alertmanager down or missing
   - alert: AlertmanagerFailedReload
     expr: alertmanager_config_last_reload_successful == 0
     for: 10m
@@ -28,3 +30,4 @@ groups:
     annotations:
       description: Reloading Alertmanager's configuration has failed for {{ $labels.namespace
         }}/{{ $labels.pod}}.
+      summary: Alertmanager's configuration reload failed