Tidy sysctl task page for GA

Author: Tim Bannister

content/en/docs/tasks/administer-cluster/sysctl-cluster.md

@@ -7,17 +7,19 @@ content_type: task
 
 <!-- overview -->
 
+{{< feature-state for_k8s_version="v1.21" state="stable" >}}
+
 This document describes how to configure and use kernel parameters within a
 Kubernetes cluster using the {{< glossary_tooltip term_id="sysctl" >}}
 interface.
 
-
-
 ## {{% heading "prerequisites" %}}
 
 
-{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
+{{< include "task-tutorial-prereqs.md" >}}
 
+For some steps, you also need to be able to reconfigure the command line
+options for the kubelets running on your cluster.
 
 
 <!-- steps -->