Updated mediawiki/extensions
Project: mediawiki/extensions/MobileFrontend  e780fdb5cb6e5f1168f191abc2998ddd99d1eea8

Hygiene: Fix VisualEditorOverlay and ZeroOverlay

These overlays do not have fixed headers. This also allows overlays
to appear in the style guide.

Change-Id: I6365e5f114e31517d55d7ee2ee9ef47eeccb40ae