Don't use self.highlight_color for AGroupBox
Don't use self.highlight_color for AGroupBox

We don't use highlighting on AGroupBox, so instead of accessing it by a
`self` property for the highlightling color, make it a keyworded
function argument.

himaaaatti/qtile,tych0/qtile,qtile/qtile,flacjacket/qtile,rxcomm/qtile,ramnes/qtile,flacjacket/qtile,ramnes/qtile,de-vri-es/qtile,kynikos/qtile,cortesi/qtile,frostidaho/qtile,zordsdavini/qtile,soulchainer/qtile,qtile/qtile,himaaaatti/qtile,dequis/qtile,zordsdavini/qtile,jdowner/qtile,rxcomm/qtile,cortesi/qtile,tych0/qtile,de-vri-es/qtile,jdowner/qtile,dequis/qtile,soulchainer/qtile,kynikos/qtile,frostidaho/qtile