Make podTemplate documentation more general (elastic#3370)

* Generalize podTemplate documentation

docs/orchestrating-elastic-stack-applications/customize-pods.asciidoc

@@ -7,7 +7,7 @@ endif::[]
 [id="{p}-{page_id}"]
 = Customize Pods
 
-You can customize the Pods created for each Elasticsearch, Kibana, or APM Server resource by modifying the respective `podTemplate` field in the manifest. Pod templates allow you to define labels, annotations, environment variables, volume mounts, and other custom configuration settings that are then merged with the default Pod configuration generated by ECK to produce the final Pod definition that gets deployed to the Kubernetes cluster.
+You can customize the Pods created for each Elastic stack application by modifying the respective `podTemplate` field in the manifest. Pod templates allow you to define labels, annotations, environment variables, volume mounts, and other custom configuration settings that are then merged with the default Pod configuration generated by ECK to produce the final Pod definition that gets deployed to the Kubernetes cluster.
 
 
 The following example illustrates how to add a custom label, annotation, and an environment variable using the `podTemplate` field.
@@ -62,7 +62,7 @@ spec:
               value: "true"
 ----
 
-NOTE: APM Server configuration is identical to the Kibana configuration except for the `apiVersion` and `kind` fields.
+NOTE: Configuration for other Elastic stack applications, like APM Server, Enterprise Search or Beats, is identical to the Kibana configuration except for the `apiVersion` and `kind` fields.
 
 The example below shows how it's also possible to customize the init containers created as part of the Pods to initialize the filesystem or to manage the keystores.