(cherry picked from commit 5ffb2581)

Forgot that this was a thing, let's update it.

As per new GTK the tests will depend on vulkan renderer, so let's add
this test dependency instead of forcing the usage of a non-default
specific renderer.

Make CI pass, hopefully.

Custom search command.

Now the demo also has proper macos style keybindings.

Similar to Safari:
https://support.apple.com/guide/safari/keyboard-and-other-shortcuts-cpsh003/mac.

This is relevant, e.g, on toolbars, where a slot with a hidden child
results in double spacing between toolbar children.

0 is unitless, so if you use --window-radius in a calc() expression with
a length and it's 0, GTK will complain.

This is a workaround for
https://gitlab.gnome.org/GNOME/glib/-/issues/3434 which is a duplicate
of https://gitlab.gnome.org/GNOME/glib/-/issues/1002.

The problem is GObject atomically destroys its list of weak notifies
when an object is disposed, *then* iterates through each notify. If one
notify tries to remove a later notify, it will fail and emit a critical.
Then the later notify will be improperly executed, leading to use after
free.

There is a solution in
https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3864, which changes
GObject to remove weak notifies just one at a time. But that is going to
take a while to land, and it's a longstanding bug. We should land a
workaround now so that applications can safely use AdwSpinner in the
meantime.

See https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/7622

Fixes https://gitlab.gnome.org/GNOME/libadwaita/-/issues/346

This reverts commit 2ff40d89

This allows text to properly scale when changing the default font size.

Fixes https://gitlab.gnome.org/GNOME/libadwaita/-/issues/733

This should fix a crash that sometimes occurs when closing a browser tab
in Epiphany. The solution is suggested by Alice.

Fixes #834

Otherwise -- gets combined into —.

Match what docs say.

Move .property to its own section, add a screenshot, and add .monospace.

Move .compact to a separate section and add a screenshot.

Move style class docs to a separate section, add separate screenshots, add
screenshots on the style classes page too, and remove destructive/suggested
styles from the main button row screenshot.

Add a header bar border instead of shadow and don't round bottom corners,
since those won't work for SSD windows.

I'll restore it once infra is fixed, for now let's be able to land things.

Fixes #924

Commit gtk@d58b545f fixed a double counting of value size, but didn't
check whether that actually looked great. It doesn't.

Because the slider has negative margins, we need to add margin to the
value if it's on a side with no marks. If it is on a side with marks,
the scale will make it touch the marks. We therefore apply a mark's size
of margin to have the value be in the same place, with or without marks.

This is the same fix as proposed in gtk!7656, which has more screenshot
for the GTK Adwaita theme.

Update to upstream version '1.6~rc'
with Debian dir 671394ed04fef57325fbd6e2d0904c7acd51ae6c