Fix comments of 5262 (#6206)

* add "for" in description: ... configure Istio for Kubernetes External Services

* add "in the default namespace" to "create a Kubernetes ExternalName Service"

* mention the Kubernetes DNS format for services

content/en/docs/tasks/traffic-management/egress/egress-kubernetes-services/index.md

@@ -1,6 +1,6 @@
 ---
 title: Kubernetes Services for Egress Traffic
-description: Shows how to configure Istio  Kubernetes External Services.
+description: Shows how to configure Istio for Kubernetes External Services.
 keywords: [traffic-management,egress]
 weight: 60
 ---
@@ -58,7 +58,7 @@ Kubernetes Services for egress traffic work with other protocols as well.
 
 1.  Create a Kubernetes
     [ExternalName](https://kubernetes.io/docs/concepts/services-networking/service/#externalname) service
-    for `httpbin.org`:
+    for `httpbin.org` in the default namespace:
 
     {{< text bash >}}
     $ kubectl apply -f - <<EOF
@@ -84,7 +84,8 @@ Kubernetes Services for egress traffic work with other protocols as well.
     my-httpbin   ExternalName   <none>       httpbin.org   80/TCP    4s
     {{< /text >}}
 
-1.  Access `httpbin.org` via the Kubernetes service's hostname from the source pod without Istio sidecar:
+1.  Access `httpbin.org` via the Kubernetes service's hostname from the source pod without Istio sidecar.
+    Note that the _curl_ command below uses the [Kubernetes DNS format for services](https://v1-13.docs.kubernetes.io/docs/concepts/services-networking/dns-pod-service/#a-records): `<service name>.<namespace>.svc.cluster.local`.
 
     {{< text bash >}}
     $ kubectl exec -it $SOURCE_POD_WITHOUT_ISTIO -n without-istio -c sleep -- curl my-httpbin.default.svc.cluster.local/headers