Add a short -n for kubectl's --namespace

fixes #24078

--namespace is a very common flag for nearly every kubectl command we have.
We should claim -n for it.

docs/devel/kubectl-conventions.md

@@ -142,6 +142,7 @@ list when adding new short flags
 
   * `-f`: Resource file
     * also used for `--follow` in `logs`, but should be deprecated in favor of `-F`
+  * `-n`: Namespace scope
   * `-l`: Label selector
     * also used for `--labels` in `expose`, but should be deprecated
   * `-L`: Label columns

hack/make-rules/test-cmd.sh

@@ -1349,6 +1349,8 @@ __EOF__
   kubectl create "${kube_flags[@]}" --namespace=other -f docs/admin/limitrange/valid-pod.yaml
   # Post-condition: valid-pod POD is created
   kube::test::get_object_assert 'pods --namespace=other' "{{range.items}}{{$id_field}}:{{end}}" 'valid-pod:'
+  # Post-condition: verify shorthand `-n other` has the same results as `--namespace=other`
+  kube::test::get_object_assert 'pods -n other' "{{range.items}}{{$id_field}}:{{end}}" 'valid-pod:'
 
   ### Delete POD valid-pod in specific namespace
   # Pre-condition: valid-pod POD exists

pkg/client/unversioned/clientcmd/overrides.go

@@ -158,7 +158,7 @@ func RecommendedContextOverrideFlags(prefix string) ContextOverrideFlags {
 	return ContextOverrideFlags{
 		ClusterName:  FlagInfo{prefix + FlagClusterName, "", "", "The name of the kubeconfig cluster to use"},
 		AuthInfoName: FlagInfo{prefix + FlagAuthInfoName, "", "", "The name of the kubeconfig user to use"},
-		Namespace:    FlagInfo{prefix + FlagNamespace, "", "", "If present, the namespace scope for this CLI request"},
+		Namespace:    FlagInfo{prefix + FlagNamespace, "n", "", "If present, the namespace scope for this CLI request"},
 	}
 }