GtkModelMenuItem: Add some property notification
GtkModelMenuItem: Add some property notification

GtkModelMenuItem emits no property notification, since none of its
properties are readable. But the toggled property is just a proxy
for GtkCheckMenuItem::active, so we should ensure that property
notification is emitted for the ::active property.

jessevdk/gtk,jessevdk/gtk,msteinert/gtk,Lyude/gtk-,grubersjoe/adwaita,Adamovskiy/gtk,davidgumberg/gtk,chergert/gtk,grubersjoe/adwaita,msteinert/gtk,chergert/gtk,Lyude/gtk-,msteinert/gtk,jadahl/gtk,alexlarsson/gtk,jessevdk/gtk,jigpu/gtk,alexlarsson/gtk,ahodesuka/gtk,ahodesuka/gtk,jessevdk/gtk,grubersjoe/adwaita,Lyude/gtk-,Sidnioulz/SandboxGtk,jigpu/gtk,Adamovskiy/gtk,ahodesuka/gtk,msteinert/gtk,grubersjoe/adwaita,ahodesuka/gtk,jadahl/gtk,jadahl/gtk,davidgumberg/gtk,jadahl/gtk,Sidnioulz/SandboxGtk,msteinert/gtk,alexlarsson/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,chergert/gtk,jigpu/gtk,msteinert/gtk,Adamovskiy/gtk,chergert/gtk,davidgumberg/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,grubersjoe/adwaita,chergert/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,Adamovskiy/gtk,Lyude/gtk-,alexlarsson/gtk,Lyude/gtk-,alexlarsson/gtk,grubersjoe/adwaita,ahodesuka/gtk,jadahl/gtk,jadahl/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,jigpu/gtk,chergert/gtk,Lyude/gtk-,Adamovskiy/gtk,davidgumberg/gtk,jessevdk/gtk,alexlarsson/gtk,jigpu/gtk,jigpu/gtk,jigpu/gtk,jigpu/gtk,Adamovskiy/gtk,ahodesuka/gtk,Adamovskiy/gtk,davidgumberg/gtk,Lyude/gtk-,chergert/gtk,jessevdk/gtk,alexlarsson/gtk,jessevdk/gtk,Adamovskiy/gtk,chergert/gtk,davidgumberg/gtk,davidgumberg/gtk,grubersjoe/adwaita,Lyude/gtk-,alexlarsson/gtk,davidgumberg/gtk,grubersjoe/adwaita