Update docs to reflect newly support shells with autocompletions (#29610)

* Update docs to reflect newly support shells with autocompletions

* Update Windows docs to use Powershell instead of zsh

* Adds a bit more explanation of the different lines.

* Apply suggestions from code review

Co-authored-by: Tim Bannister <tim@scalefactory.com>

* Apply PR suggestions

Co-authored-by: Tim Bannister <tim@scalefactory.com>

content/en/docs/tasks/tools/included/optional-kubectl-configs-pwsh.md

@@ -0,0 +1,23 @@
+---
+title: "PowerShell auto-completion"
+description: "Some optional configuration for powershell auto-completion."
+headless: true
+---
+
+The kubectl completion script for PowerShell can be generated with the command `kubectl completion powershell`.
+
+To do so in all your shell sessions, add the following line to your `$PROFILE` file:
+
+```powershell
+kubectl completion powershell | Out-String | Invoke-Expression
+```
+
+This command will regenerate the auto-completion script on every PowerShell start up. You can also add the generated script directly to your `$PROFILE` file.
+
+To add the generated script to your `$PROFILE` file, run the following line in your powershell prompt:
+
+```powershell
+kubectl completion powershell >> $PROFILE
+```
+
+After reloading your shell, kubectl autocompletion should be working.