adds syntax highlighting and trims trailing whitespace

docs/10-configuring-kubectl.md

@@ -10,7 +10,7 @@ Each kubeconfig requires a Kubernetes API Server to connect to. To support high
 
 Generate a kubeconfig file suitable for authenticating as the `admin` user:
 
-```
+```sh
 {
   KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
     --region $(gcloud config get-value compute/region) \
@@ -37,7 +37,7 @@ Generate a kubeconfig file suitable for authenticating as the `admin` user:
 
 Check the health of the remote Kubernetes cluster:
 
-```
+```sh
 kubectl get componentstatuses
 ```
 
@@ -54,7 +54,7 @@ etcd-0               Healthy   {"health":"true"}
 
 List the nodes in the remote Kubernetes cluster:
 
-```
+```sh
 kubectl get nodes
 ```