chore: Use shortcut widgets

[vanillajonathan]

Use dedicated shortcut widgets instead of boxes and labels.

[dynobo]

I appreciate the contribution, but since ShortcutsSection is deprecated, it feels like not sustainable to introduce it, when it already is clear, that it has to be removed again sooner or later. What do you think?

[vanillajonathan]

Yes, the widgets are deprecated because they have been moved from GTK to Adwaita in Adwaita v1.8.

I think we should merge it, then when the new version of Adwaita is released, we migrate to the Adw widgets which have a similar API and will be very easy migrate over to.

[dynobo]

[...] when the new version of Adwaita is released, we migrate to the Adw widgets which have a similar API and will be very easy migrate over to.

Do you have any link to the documentation for those Adwaita widgets?

I do not want to introduce code into the project, which is already deprecated. This also follows GTK's recommendation.

But if Adwaita has widgets for displaying key bindings, I'd happily consider using those!

[vanillajonathan]

Yes, the documentation is at https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/class.ShortcutsDialog.html but new widgets will be introduced in Adwaita 1.8.

[dynobo]

Thanks, @vanillajonathan. Let's then wait for the Adwaita 1.8 final release, and after that switch directly to the adwaita shortcut widgets.

[dynobo]

This PR got superseeded by #35, which updates to GTK 4.20 with Libadwaita 1.8 and implements the ShortcutsDialog.