Add fix for error in kubeadm ref pages (#8374)

* add kubeadm-reset.md introductory text

* Added introductory text

* Fixed single quotes

content/en/docs/reference/setup-tools/kubeadm/kubeadm-init.md

@@ -7,9 +7,11 @@ title: kubeadm init
 content_template: templates/concept
 ---
 {{% capture overview %}}
+This command initializes a Kubernetes master node.
 {{% /capture %}}
 
 {{% capture body %}}
+
 {{< include "generated/kubeadm_init.md" >}}
 
 ### Init workflow {#init-workflow}

content/en/docs/reference/setup-tools/kubeadm/kubeadm-join.md

@@ -7,6 +7,7 @@ title: kubeadm join
 content_template: templates/concept
 ---
 {{% capture overview %}}
+This command initializes a Kubernetes worker node and joins it to the cluster. 
 {{% /capture %}}
 
 {{% capture body %}}

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

@@ -7,6 +7,7 @@ title: kubeadm reset
 content_template: templates/concept
 ---
 {{% capture overview %}}
+This command reverts any changes made by `kubeadm init` or `kubeadm join`.
 {{% /capture %}}
 
 {{% capture body %}}

content/en/docs/reference/setup-tools/kubeadm/kubeadm-version.md

@@ -7,6 +7,7 @@ title: kubeadm version
 content_template: templates/concept
 ---
 {{% capture overview %}}
+This command prints the verison of kubeadm.
 {{% /capture %}}
 
 {{% capture body %}}