Merge pull request #37031 from foxish/add-ss-kubectl

Automatic merge from submit-queue

Adding statefulset to the list of things kubectl says it knows about

**What this PR does / why we need it**: Adding statefulset to the list of things kubectl says it knows about.

**Special notes for your reviewer**: 

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cc @kubernetes/sig-apps @erictune

pkg/kubectl/cmd/cmd.go

@@ -195,6 +195,7 @@ __custom_func() {
     * secrets
     * serviceaccounts (aka 'sa')
     * services (aka 'svc')
+    * statefulsets
     * storageclasses
     * thirdpartyresources
     `