dash: Fix background hovering effect

[ran-dall]

(...in a way continues #190)

As noted by @pasan93 in #190 (comment), the hovering effect wasn't working.

@EliverLara This PR fixes that on the dash branch. Also, the formatting uses dart-sass hence all the trivial style differences.

[EliverLara]

Is it just me or does it look like the _dash-to-dock.scss file hasn't been rendered in gtk.css?

[ran-dall]

@EliverLara Is it supposed to render in gtk.css? I think if it is, then maybe the Gulpfile.js needs an update cause it's not set up to render changes in gnome-shell outside of ./gnome-shell. I believe gtk.css is inside gtk-4.0 so it won't get rendered because it isn't gnome-shell (which only renders out to ./gnome-shell/).

BTW there are no rules on Gulp to render out to gtk-4.0, I just noticed. It's still set up to 3.20 only. Maybe I'll do that later today and add it to #193.

[EliverLara]

I'm sorry, I meant gnome-shell.css

[ran-dall]

@EliverLara What did you want to do about this? I see that we're already several commits out of alignment with the main tree. Did you want to work on #193 first, so we can establish the right syntax rules for newer contributors, such as myself?

[EliverLara]

@ran-dall Sorry for the delayed reply, I just merged it and I'll add it to the master branch, thank you so much for your contributions!, now I'll take a look to #193 in order to provide feedback to you.