Fix links on first page "Learn" - "What is Powershell Gallery" and "Getting Started"

[LUCScape]

To be fixed, on PowerShell Gallery homepage:

"What is PowerShell Gallery?" old link: https://docs.microsoft.com/en-us/powershell/gallery/overview New link: https://docs.microsoft.com/en-us/powershell/scripting/gallery/overview

"Getting started" old link: https://docs.microsoft.com/en-us/powershell/gallery/getting-started New link: https://docs.microsoft.com/en-us/powershell/scripting/gallery/getting-started

[alerickson]

These are fixed now, thanks!