Localisation updates from https://translatewiki.net.

Change-Id: Ib74e375df62c27ed1dee20c015db9e84145e935b
Migrate to JSON i18n

Procedure per https://www.mediawiki.org/wiki/Manual:GenerateJsonI18n.php
with shim.

Change-Id: I750760836cd65848b3d90fe760c8873ea7203c92
Fix spelling: 'occurred' and whitespace

Change-Id: I592ab9b521602efd388748a7c1f6e7fab9d94455