Merge recent changes of master branch

Localisation updates from https://translatewiki.net.

Change-Id: Iebef6dc1e822dc0ad1ceb1196000f85154dfe001

Localisation updates from https://translatewiki.net.

Change-Id: I75735349d80637af9f1b0c259cfaee3f4ba7fc1a

MathJax must not process every <strong class="error">

Many things in MediaWiki (and various on-wiki templates, at least on
enwiki) output error messages wrapped in <strong class="error">. MathJax
parsing all of these (added in I1199cb34) is completely broken.

What appears to have been intended is that MathJax would parse the
errors output by MathRenderer.php. So let's add a "texerror" class to
those and have MathJax look for that class instead.

Bug: 55675
Change-Id: Iaa6c3a892af463f38e6706f9407c6dcb948fe670

Localisation updates from https://translatewiki.net.

Change-Id: Icf563562f630d51bbcd6cd8fc9eba7450e0da999

Localisation updates from https://translatewiki.net.

Change-Id: I3d0f880fb9d10277448702c2ac3273880bbab570

Localisation updates from https://translatewiki.net.

Change-Id: I3daade8f386280ed0dee058e117711cebaaea903