window: Change button order, remove `linked`
- We shouldn't use
.linked
for header/toolbar buttons, per https://blogs.gnome.org/alexm/2021/09/10/cleaning-up-header-bars/ - In other apps, back/forward buttons are at the very beginning of the headerbar.
.linked
for header/toolbar buttons,
per https://blogs.gnome.org/alexm/2021/09/10/cleaning-up-header-bars/