Enhancements in clarity to access-application-cluster/connecting-frontend-backend.md (#25927)

* Enhancements in clarity to docs/tasks/access-application-cluster/connecting-frontend-backend.md

* Code review comments

* Reverting name of service due to backed value in Dockerimage

content/en/examples/service/access/backend-deployment.yaml

@@ -0,0 +1,26 @@
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: backend
+spec:
+  selector:
+    matchLabels:
+      app: hello
+      tier: backend
+      track: stable
+  replicas: 3
+  template:
+    metadata:
+      labels:
+        app: hello
+        tier: backend
+        track: stable
+    spec:
+      containers:
+        - name: hello
+          image: "gcr.io/google-samples/hello-go-gke:1.0"
+          ports:
+            - name: http
+              containerPort: 80
+...