Add API appeared in 2.20 but not marked as such in gio docs
Add API appeared in 2.20 but not marked as such in gio docs

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