gtk: Allow selection models to take null list model during construction
The functions gtk_single_selection_new
gtk_multi_selection_new
and gtk_no_selection_new
were documented as taking a NULL model, and the gir definitions are marking this as nullable, but they fail with a NULL model, this should fix it. This brings consistency with the *_set_model
functions for those classes, which do successfully take a NULL model.
Edited by Jason Francis