device: Add more doc annotations
device: Add more doc annotations

Even for internal API.

collects/clutter,jigpu/clutter,djdeath/clutter,dlespiau/clutter,djdeath/clutter-multithreaded,djdeath/clutter-multithreaded,jigpu/clutter,Distrotech/clutter,GNOME/clutter,heysion/clutter-clone,djdeath/clutter-multithreaded,GNOME/clutter,ebassi/clutter,jigpu/clutter,nobled/clutter,spatulasnout/clutter,spatulasnout/clutter,jigpu/clutter,ebassi/clutter,djdeath/clutter,collects/clutter,djdeath/clutter,ebassi/clutter,djdeath/clutter-android,GNOME/clutter,spatulasnout/clutter,spatulasnout/clutter,collects/clutter,Distrotech/clutter,djdeath/clutter-android,Distrotech/clutter,kerrickstaley/clutter-vala,jigpu/clutter,dlespiau/clutter,djdeath/clutter,collects/clutter,djdeath/clutter-android,Distrotech/clutter,GNOME/clutter,heysion/clutter-clone,djdeath/clutter,nobled/clutter,kerrickstaley/clutter-vala,jigpu/clutter,kerrickstaley/clutter-vala,heysion/clutter-clone,heysion/clutter-clone,Distrotech/clutter,ebassi/clutter,djdeath/clutter-multithreaded,collects/clutter,spatulasnout/clutter,GNOME/clutter,kerrickstaley/clutter-vala,djdeath/clutter-android,nobled/clutter,Distrotech/clutter,dlespiau/clutter,ebassi/clutter,heysion/clutter-clone,djdeath/clutter,djdeath/clutter-android