Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  8ca53618caba6a7e80a082dc451655003d6e5c43

Use correct plural form

This is somewhat superflawous as the message itself will not be used
in a singular form. That is it is not part of that code part.

Change-Id: Id38d3308cfc0bb7bfd63f316dab3ed4824519d21