build: Remove unnecessary argument for gtkdoc-scan
build: Remove unnecessary argument for gtkdoc-scan

We don't use deprecation guards any more, in favour of compiler
annotations and gtk-doc annotations.

Distrotech/clutter,GNOME/clutter,Distrotech/clutter,Distrotech/clutter,Distrotech/clutter,jigpu/clutter,jigpu/clutter,jigpu/clutter,Distrotech/clutter,GNOME/clutter,GNOME/clutter,GNOME/clutter,jigpu/clutter,jigpu/clutter,GNOME/clutter,Distrotech/clutter,jigpu/clutter