Update eck-stack-monitoring.md

The example for "Connect to an external monitoring elasticsearch cluster" can lead to confusion or seem to be incorrect, so I added a small explanation about what the config in the example does

Author: laraMorenoIgle

deploy-manage/monitor/stack-monitoring/eck-stack-monitoring.md

@@ -116,7 +116,9 @@ If Logs stack monitoring is configured for a Beat, and custom container argument
 
 ## Connect to an external monitoring {{es}} cluster [k8s_connect_to_an_external_monitoring_elasticsearch_cluster]
 
-If you want to connect to a monitoring {{es}} cluster not managed by ECK, you can reference a Secret instead of an {{es}} cluster in the `monitoring` section through the `secretName` attribute:
+If you want to connect to a monitoring {{es}} cluster not managed by ECK, you can reference a Secret instead of an {{es}} cluster in the `monitoring` section through the `secretName` attribute.
+
+Next example sends cluster metrics to a remote monitoring cluster not managed by ECK, whereas cluster logs are sent to a remote cluster handled by ECK.
 
 ```yaml
 apiVersion: elasticsearch.k8s.elastic.co/v1
@@ -193,4 +195,4 @@ spec:
         - name: filebeat
           env:
           - foo: bar
-```
+```