docs(listener): Update service exposition docs

Author: NickLarsenNZ

docs/modules/zookeeper/pages/usage_guide/listenerclass.adoc

@@ -2,15 +2,14 @@
 
 Apache ZooKeeper offers an API. The Operator deploys a service called `<name>` (where `<name>` is the name of the ZookeeperCluster) through which ZooKeeper can be reached.
 
-This service can have either the `cluster-internal` or `external-unstable` type. `external-stable` is not supported for ZooKeeper at the moment.
-Read more about the types in the xref:concepts:service-exposition.adoc[service exposition] documentation at platform level.
-
-This is how the listener class is configured:
+The operator deploys a xref:listener-operator:listener.adoc[Listener] for the Server pod.
+The listener defaults to only being accessible from within the Kubernetes cluster, but this can be changed by setting `.spec.nodes.config.listenerClass`:
 
 [source,yaml]
 ----
 spec:
-  clusterConfig:
-    listenerClass: cluster-internal  # <1>
+  servers:
+    config:
+      listenerClass: external-unstable  # <1>
 ----
-<1> The default `cluster-internal` setting.
+<1> Specify one of `external-stable`, `external-unstable`, `cluster-internal` (the default setting is `cluster-internal`).