
Avoid the GTK dependency, and use the common GLib API to store screenshots in recent files. While at it, give it a better exec hint than the implicit "gnome-shell %u" GTK added for us, nobody seems to pay attention to that, but if they ever did it's better to provide sensible information. Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2656>