Merge branch 'wip/surface-state-rework' into 'master'

Rework surface state and geometry computation

See merge request GNOME/gtk!2885

diff --cc docs/reference/gtk/gtk4-sections.txt
Simple merge

diff --cc gtk/gtkexpander.c
Simple merge

diff --cc gtk/gtklabel.c
Simple merge

diff --cc gtk/gtkpopovermenubar.c
Simple merge

diff --cc gtk/gtkwidget.c
Simple merge

diff --cc gtk/gtkwidgetprivate.h
Simple merge