[GTK] Fix spinner
[GTK] Fix spinner

The GType property was missing
mminns/xwt,antmicro/xwt,akrisiun/xwt,TheBrainTech/xwt,directhex/xwt,steffenWi/xwt,iainx/xwt,residuum/xwt,mono/xwt,hwthomas/xwt,cra0zy/xwt,hamekoz/xwt,sevoku/xwt,mminns/xwt,lytico/xwt