kubeadm: Improve kubeadm documentation for v1.9 (#6645)

docs/reference/setup-tools/kubeadm/kubeadm-reset.md

@@ -12,15 +12,16 @@ title: kubeadm reset
 {% include_relative generated/kubeadm_reset.md %}
 
 ### External etcd clean up
+
 `kubeadm reset` will not delete any etcd data if external etcd is used. This means that if you run `kubeadm init` again using the same etcd endpoints, you will see state from previous clusters. 
 
 To wipe etcd data it is recommended you use a client like etcdctl, such as:
 
-```
+```bash
 etcdctl del "" --prefix
 ```
 
-See [etcd documentation](https://github.com/coreos/etcd/tree/master/etcdctl) for more information.
+See the [etcd documentation](https://github.com/coreos/etcd/tree/master/etcdctl) for more information.
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