The script is available for download from http://gallery.technet.microsoft.com/Add-the-Pin-to-Start-1c0156a3. You can also use Microsoft Script Browser for Windows PowerShell ISE to download the sample with one button click from within your scripting environment.
This PowerShell script sample shows how to add the "Pin to Start Screen" context menu item to all files in Windows 8.1
With Windows 8.1, Microsoft has restricted access to the 'Pin to Start Screen' menu command for 3rd party apps. The same thing could be implemented in Windows 8. Any app was able to pin itself to the Start Screen, but not so in Windows 8.1. So this script can get the "Pin to Start Screen" context menu item unlocked for every file, and every file system object in Explorer.
You can find more All-In-One Script Framework script samples at https://aka.ms/onescriptingallery