Add function macros
We're parsing them from the GIR, but we don't emit anything when generating the API reference.
This makes functions like gtk_widget_class_bind_template()
disappear into a black hole.
Issues:
- we want
gtk_widget_class_bind_template()
and friends, but notGTK_WIDGET_GET_CLASS()
- function macros exist in the global namespace, so links will have to go through the
func@
fragment - there is no nice
moved-to
equivalent for function macros, so we can't havefunc@Gtk.WidgetClass.bind_template