Updated mediawiki/extensions
Project: mediawiki/extensions/Agora  957b6e3d372bac20d74eac7c66fc3db3c7a68257

Merge button-group test folder

This was accidentally lost in the button-group feature merge.

Change-Id: I4689c1342c1653e5106d10d4543d28c2d3a4eb3a