Updated mediawiki/extensions
Project: mediawiki/extensions/Math  97d6f8ff899feb007c4d8fa643cbb30c0e0df221

Work around tidy by using a meta element instead of an empty span

HTML tidy will strip empty spans, so don't use one for the fallback image. We
use a meta element instead, as that does not normally render at all & doesn't
have any default styling coming with it.

Change-Id: I5bcbbc9468433e3c8722c09ce813a6f5ac741333