Update PowerShell_for_Github.md

Author: awsles

GITHUB/PowerShell_for_Github.md

@@ -2,7 +2,8 @@
 In some circumstances, you may wish to use github via PowerShell such as in an Azure runbook where
 the `$git` command may not be available.
 
-https://www.powershellgallery.com/packages/PowerShellForGitHub/
+* Install from: https://www.powershellgallery.com/packages/PowerShellForGitHub/
+* Source code: https://github.com/Microsoft/PowerShellForGitHub
 
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