Add details in kubeadm-reconfigure.md for etcd

The kubeadm init phase doesn't permit to reconfigure the etcd yaml manifest (when etcd is in local mode)
Adding the right command when etcd needs to be reconfigured

Co-authored-by: Lubomir I. Ivanov 

Author: zwindler

content/en/docs/tasks/administer-cluster/kubeadm/kubeadm-reconfigure.md

@@ -99,11 +99,14 @@ kubeadm init phase certs  --config 
 To write new manifest files in `/etc/kubernetes/manifests` you can use:
 
 ```shell
+# For Kubernetes control plane components
 kubeadm init phase control-plane <component-name> --config <config-file>
+# For local etcd
+kubeadm init phase etcd local --config <config-file>
 ```
 
 The `` contents must match the updated `ClusterConfiguration`.
-The `` value must be the name of the component.
+The `` value must be a name of a Kubernetes control plane component (`apiserver`, `controller-manager` or `scheduler`).
 
 {{< note >}}
 Updating a file in `/etc/kubernetes/manifests` will tell the kubelet to restart the static Pod for the corresponding component.