Updated mediawiki/extensions
Project: mediawiki/extensions/Flow  4a1c98210b097424456d517f0b4b71b7d446097b

Hygiene: Improve FlowActions docs and remove dead code

* Add/clarify a couple documentation comments
* Remove button-method, which is dead

Change-Id: Ifee32554f905c25fc6813bc059765736e0d1391e