Add config API for kubelet stats v1alpha1

Author: tengqm

content/en/docs/reference/_index.md

@@ -84,6 +84,7 @@ operator to use or manage a cluster.
   [kubelet configuration (v1beta1)](/docs/reference/config-api/kubelet-config.v1beta1/)
   [kubelet configuration (v1)](/docs/reference/config-api/kubelet-config.v1/)
 * [kubelet credential providers (v1)](/docs/reference/config-api/kubelet-credentialprovider.v1/)
+* [kubelet stats (v1)](/docs/reference/config-api/kubelet-stats.v1/)
 * [kube-scheduler configuration (v1beta3)](/docs/reference/config-api/kube-scheduler-config.v1beta3/) and
   [kube-scheduler configuration (v1)](/docs/reference/config-api/kube-scheduler-config.v1/)
 * [kube-controller-manager configuration (v1alpha1)](/docs/reference/config-api/kube-controller-manager-config.v1alpha1/)