This gets us out of using direct presentational
markup like 'inverted' and 'centered' and will
make it easier to play with different layout.
Use the new role when creating popover
menus from models.
Remove all the old 2.x and 3.x version annotations.
GTK+ 4 is a new start, and from the perspective of a
GTK+ 4 developer all these APIs have been around since
the beginning.
Similar in spirit to GtkModelMenuItem, this private GtkButton subclass
can connect to a GtkMenuTrackerItem and present itself as either a
regular button, a check button, or a radio button. Activation and
state tracking is done through the GAction that is associated with
the menu tracker item.
https://bugzilla.gnome.org/show_bug.cgi?id=723014
