Updated mediawiki/extensions
Project: mediawiki/extensions/GettingStarted  5ec4338bbac62fbf410d7c4e1b151fd26b9f70ea

Clarify that PageImages is required for morelike

Also explain when morelike is used.

Change-Id: Ibfaa449c2b8840520b734c7166d5fe1a939aa8d7