A property for reversing the visible order of children is a bit odd.
It has also been unused by actual gnome-shell code since 2010, and the
somewhat related pack_start()/pack_end() API in GtkBox(Layout) is gone
in GTK4.
With that in mind, turn the property into a no-op and deprecate it,
so that it can be dropped next cycle.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2206>
This stuff has been deprecated for a very long time, and given that
ClutterBoxLayout is most commonly used via StBoxLayout, the impact of
removing it should be low. It will however open the door to further
cleanups.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1265
In the past, it was a odd mix of possible different types, all coalesced
into an unsigned integer. Now, hovewer, it's always a
ClutterAnimationType, so lets change the name of getter, setter and
property to what it really is.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1192
