Correct description of kubectl (#18172)

* Correct description of kubectl

Given that `kubectl` is not a [command line interface (CLI)](https://en.wikipedia.org/wiki/Command-line_interface), I suggest calling it what it is -- a control utility (ctl = control). The term "tool" is commonly used in place of "utility," including the `kubectl` docs.

A CLI presents the user with a command prompt at which the user can enter multiple command lines that a command-line interpreter interprets and processes. Think of `bash`, `emacs`, or a SQL shell.  Since `kubectl` is not run in a shell, it is not a CLI.

Here are related docs that correctly refer to `kubectl` as a "command-line tool":

- https://kubernetes.io/docs/reference/tools/#kubectl
- https://kubernetes.io/docs/reference/glossary/?fundamental=true#term-kubectl
- https://kubernetes.io/docs/tasks/tools/install-kubectl/
- https://kubernetes.io/docs/reference/kubectl/kubectl/

* Update content/en/docs/reference/kubectl/overview.md

Co-Authored-By: Zach Corleissen <[email protected]>

Co-authored-by: Zach Corleissen <[email protected]>

content/en/docs/reference/kubectl/overview.md

@@ -10,7 +10,7 @@ card:
 ---
 
 {{% capture overview %}}
-Kubectl is a command line interface for running commands against Kubernetes clusters. `kubectl` looks for a file named config in the $HOME/.kube directory. You can specify other [kubeconfig](/docs/concepts/configuration/organize-cluster-access-kubeconfig/) files by setting the KUBECONFIG environment variable or by setting the [`--kubeconfig`](/docs/concepts/configuration/organize-cluster-access-kubeconfig/) flag.
+Kubectl is a command line tool for controlling Kubernetes clusters. `kubectl` looks for a file named config in the $HOME/.kube directory. You can specify other [kubeconfig](/docs/concepts/configuration/organize-cluster-access-kubeconfig/) files by setting the KUBECONFIG environment variable or by setting the [`--kubeconfig`](/docs/concepts/configuration/organize-cluster-access-kubeconfig/) flag.
 
 This overview covers `kubectl` syntax, describes the command operations, and provides common examples. For details about each command, including all the supported flags and subcommands, see the [kubectl](/docs/reference/generated/kubectl/kubectl-commands/) reference documentation. For installation instructions see [installing kubectl](/docs/tasks/kubectl/install/).