[gi] switch from using (*arg). to arg-> when referencing union memebers
[gi] switch from using (*arg). to arg-> when referencing union memebers

MathieuDuponchelle/pygobject,davidmalcolm/pygobject,davibe/pygobject,GNOME/pygobject,jdahlin/pygobject,pexip/pygobject,davibe/pygobject,sfeltman/pygobject,davibe/pygobject,sfeltman/pygobject,GNOME/pygobject,sfeltman/pygobject,choeger/pygobject-cmake,jdahlin/pygobject,jdahlin/pygobject,pexip/pygobject,choeger/pygobject-cmake,davidmalcolm/pygobject,pexip/pygobject,davibe/pygobject,thiblahute/pygobject,choeger/pygobject-cmake,thiblahute/pygobject,MathieuDuponchelle/pygobject,GNOME/pygobject,davidmalcolm/pygobject,thiblahute/pygobject,MathieuDuponchelle/pygobject