recommend usage of named port for services without selectors

Signed-off-by: Daman Arora <[email protected]>

Author: aroradaman

content/en/docs/concepts/services-networking/service.md

@@ -216,7 +216,8 @@ metadata:
   name: my-service
 spec:
   ports:
-    - protocol: TCP
+    - name: http
+      protocol: TCP
       port: 80
       targetPort: 9376
 ```
@@ -238,8 +239,7 @@ metadata:
     kubernetes.io/service-name: my-service
 addressType: IPv4
 ports:
-  - name: '' # empty because port 9376 is not assigned as a well-known
-             # port (by IANA)
+  - name: http # should match with the name of the service port defined above
     appProtocol: http
     protocol: TCP
     port: 9376