Merge pull request #42336 from superbrothers/context-completion-for-config-use-context

Automatic merge from submit-queue (batch tested with PRs 44119, 42538, 43802, 42336, 43396)

Support context completion for kubectl config use-context

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

With this PRt, kubectl is supported context completion for config use-context.

```
$ ./kubectl config use-context
cluster01  minikube
```

/ref  #42103 

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

#29386

**Special notes for your reviewer**:

**Release note**:

```release-note
```

pkg/kubectl/cmd/cmd.go

@@ -170,6 +170,10 @@ __custom_func() {
             __kubectl_get_resource_node
             return
             ;;
+        kubectl_config_use-context)
+            __kubectl_get_contexts
+            return
+            ;;
         *)
             ;;
     esac