Localisation updates from https://translatewiki.net.

Change-Id: I69d18ba63a65e9d9108f44534bbd79f5608515a3
Migrate to JSON i18n

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

Change-Id: I47e3fc5d274c9632d071d0c4e13df111f0042b17
Fix spelling: occurred

Change-Id: I6b81425eae02de939d3bd6d1a80ed677b9ea95b6