Merge pull request kubernetes#33275 from maciaszczykm/remove-kubectl-…

…namespace-cmd

Automatic merge from submit-queue

Remove kubectl namespace command

**What this PR does / why we need it**:

It removes deprecated `kubectl namespace` command, which `has been superseded by the context.namespace field of .kubeconfig files.  See 'kubectl config set-context --help' for more details`. It was done nearly two years ago, so like `// TODO remove once people have been given enough time to notice` comment says it may be a good time to get rid of it.

**Special notes for your reviewer**:

None ATM.

**Release note**:
<!--  Steps to write your release note:
1. Use the release-note-* labels to set the release note state (if you have access) 
2. Enter your extended release note in the below block; leaving it blank means using the PR title as the release note. If no release note is required, just write `NONE`. 
-->
```release-note
Remove kubectl namespace command
```

.generated_docs

@@ -57,7 +57,6 @@ docs/man/man1/kubectl-expose.1
 docs/man/man1/kubectl-get.1
 docs/man/man1/kubectl-label.1
 docs/man/man1/kubectl-logs.1
-docs/man/man1/kubectl-namespace.1
 docs/man/man1/kubectl-options.1
 docs/man/man1/kubectl-patch.1
 docs/man/man1/kubectl-port-forward.1
@@ -131,7 +130,6 @@ docs/user-guide/kubectl/kubectl_expose.md
 docs/user-guide/kubectl/kubectl_get.md
 docs/user-guide/kubectl/kubectl_label.md
 docs/user-guide/kubectl/kubectl_logs.md
-docs/user-guide/kubectl/kubectl_namespace.md
 docs/user-guide/kubectl/kubectl_options.md
 docs/user-guide/kubectl/kubectl_patch.md
 docs/user-guide/kubectl/kubectl_port-forward.md
@@ -176,7 +174,6 @@ docs/yaml/kubectl/kubectl_expose.yaml
 docs/yaml/kubectl/kubectl_get.yaml
 docs/yaml/kubectl/kubectl_label.yaml
 docs/yaml/kubectl/kubectl_logs.yaml
-docs/yaml/kubectl/kubectl_namespace.yaml
 docs/yaml/kubectl/kubectl_options.yaml
 docs/yaml/kubectl/kubectl_patch.yaml
 docs/yaml/kubectl/kubectl_port-forward.yaml

pkg/kubectl/cmd/cmd.go

@@ -315,7 +315,6 @@ Find more information at https://github.com/kubernetes/kubernetes.`,
 	filters := []string{
 		"options",
 		Deprecated("kubectl", "delete", cmds, NewCmdStop(f, out)),
-		Deprecated("kubectl", "config set-context", cmds, NewCmdNamespace(out)),
 	}
 	templates.ActsAsRootCommand(cmds, filters, groups...)