Localisation updates from http://translatewiki.net.

Change-Id: Iab268ced3d0661117052dff0d70a5459527238b0
Consistency tweak: article -> page

"article" is Wikipedia speak. "page" is neutral
Spotted by Stryn
https://translatewiki.net/wiki/Thread:Support/MediaWiki:Wikibase-sitelinks-link-columnheading/en

Change-Id: I5922282be70f1871b97ea51eca6a81e5a8d81fc2
(bug 55937) remove duplicate datatypes-type-quantity message in Wikibase
Lib

The message in DataTypes extension is the same and sufficient for
our purposes.

Additional data type messages should only be put in Wikibase
if it is not in DataTypes and is Wikibase-specific.

Change-Id: I455f9fbedfc3fb22456141a93c919315700b9a94
Merge "(bug 55937) remove duplicate datatypes-type-quantity message in Wikibase Lib"
Fix comment in ApiWikibase that is not correct

Change-Id: Iba3f93e2c2e565da3f4c77b9dc9d65cc97e308c2