Add PowerShell module docs on Microsoft Learn

[mdanish-kh]

Brief description of your issue

Docs regarding powershell module should be added to https://learn.microsoft.com/en-us/windows/package-manager/winget/ for better discovery of module and use cases that it targets.

[mdanish-kh]

Just as an FYI for anyone who stumbles on the issue, one can currently use Get-Help Microsoft.WinGet.Client OR Get-Help <cmdlet_name like Update-WinGetPackage> -Full in PowerShell to see documentation on a certain cmdlet