Updated mediawiki/extensions
Project: mediawiki/extensions/VectorBeta  f9949a2dc1584d6ed8cd0c9702bbe67981fb5d4c

Tweak fixed header behaviour

Make it feel more responsive
Introduce small gap a la Winter mockup between left border
of search and top of screen

Change-Id: Id395257cd722a3363c7062bd1e10eee4f8e32805