Improvements to ImagePullSecrets section of the images.md doc.

Add an example for .docker/config.json based Secret config. Also, some
other minor corrections.

docs/user-guide/images.md

@@ -215,8 +215,8 @@ Kubernetes supports specifying registry keys on a pod.
 Run the following command, substituting the appropriate uppercase values:
 
 ```console
-$ kubectl create secret docker-registry my-registry-secret --docker-server=DOCKER_REGISTRY_SERVER --docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD --docker-email=DOCKER_EMAIL
-secret "my-registry-secret" created.
+$ kubectl create secret docker-registry myregistrykey --docker-server=DOCKER_REGISTRY_SERVER --docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD --docker-email=DOCKER_EMAIL
+secret "myregistrykey" created.
 ```
 
 If you need access to multiple registries, you can create one secret for each registry.
@@ -239,6 +239,19 @@ Be sure to:
   as the value for field `data[".dockerconfigjson"]`
 - set `type` to `kubernetes.io/dockerconfigjson`
 
+Example:
+
+```yaml
+apiVersion: v1
+kind: Secret
+metadata:
+  name: myregistrykey
+  namespace: awesomeapps
+data:
+  .dockerconfigjson: UmVhbGx5IHJlYWxseSByZWVlZWVlZWVlZWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWxsbGxsbGxsbGxsbGxsbGxsbGxsbGxsbGxsbGxsbGx5eXl5eXl5eXl5eXl5eXl5eXl5eSBsbGxsbGxsbGxsbGxsbG9vb29vb29vb29vb29vb29vb29vb29vb29vb25ubm5ubm5ubm5ubm5ubm5ubm5ubm5ubmdnZ2dnZ2dnZ2dnZ2dnZ2dnZ2cgYXV0aCBrZXlzCg==
+type: kubernetes.io/dockerconfigjson
+```
+
 If you get the error message `error: no objects passed to create`, it may mean the base64 encoded string is invalid.
 If you get an error message like `Secret "myregistrykey" is invalid: data[.dockerconfigjson]: invalid value ...` it means
 the data was successfully un-base64 encoded, but could not be parsed as a `.docker/config.json` file.
@@ -253,6 +266,7 @@ apiVersion: v1
 kind: Pod
 metadata:
   name: foo
+  namespace: awesomeapps
 spec:
   containers:
     - name: foo