Unused QRect when drawing slider gutter

[JulienMaille]

https://github.com/randrew/phantomstyle/blob/6e9580b72e372b5acecd616434eaf441bf73bcf4/src/phantom/phantomstyle.cpp#L3916-L3925 g0 is adjusted but not used, did you plan to call

   Ph::paintBorderedRoundRect(painter, g0, Ph::SliderGroove_Rounding, 
                              swatch, outlineColor, gutterColor);