gtk4, gtk3/windowcontrols: extend control area to window borders
This makes GTK4 window control buttons follow Fitts' law.
For libadwaita, hover icon is broken, possibly caused by https://github.com/GNOME/libadwaita/blob/52c20616605474e39cbb62ef744338884eb939da/src/stylesheet/widgets/_header-bar.scss#L106
Edited by Fushan Wen