Fix renamed POSH module (SharePoint#4085)

- fixes 3892

Author: andrewconnell

docs/sp-add-ins/use-an-office-365-sharepoint-site-to-authorize-provider-hosted-add-ins-on-an-on.md

@@ -197,7 +197,7 @@ param(
     #Import the Microsoft Online Services Sign-In Assistant.
     Import-Module -Name MSOnline
     #Import the Microsoft Online Services Module for Windows PowerShell.
-    Import-Module MSOnlineExtended -force -verbose 
+    Import-Module MSOnlineExt -force -verbose 
     #Set values for Constants.
     New-Variable -Option Constant -Name SP_APPPRINCIPALID -Value '00000003-0000-0ff1-ce00-000000000000' | Out-Null
     New-Variable -Option Constant -Name ACS_APPPRINCIPALID -Value '00000001-0000-0000-c000-000000000000' | Out-Null