Add uncordon step to containerd migration doc (#41796)

* Add uncordon step

Added a step to uncordon the node since it was drained at the beginning of this process.

* Update change-runtime-containerd.md

One more edit to the wording

* Move the uncordon step to the end and reword previous step.

content/en/docs/tasks/administer-cluster/migrating-from-dockershim/change-runtime-containerd.md

@@ -133,7 +133,7 @@ Run `kubectl get nodes -o wide` and containerd appears as the runtime for the no
 
 {{% thirdparty-content %}}
 
-Finally if everything goes well, remove Docker.
+If the node appears healthy, remove Docker.
 
 {{< tabs name="tab-remove-docker-engine" >}}
 {{% tab name="CentOS" %}}
@@ -168,3 +168,11 @@ To delete them, follow Docker's instructions to [Uninstall Docker Engine](https:
 {{< caution >}}
 Docker's instructions for uninstalling Docker Engine create a risk of deleting containerd. Be careful when executing commands.
 {{< /caution >}}
+
+## Uncordon the node 
+
+```shell
+kubectl uncordon <node-to-uncordon>
+```
+
+Replace `<node-to-uncordon>` with the name of your node you previously drained.