[feature request] highlight workspace when a window demands attention

Hello Andy!

Thank you for the great extension!

I'm a recent convert from arch+i3 to fedora+gnome, so I'm using the following for the closes to my former i3 UX:
- https://extensions.gnome.org/extension/4343/simply-workspaces/
- https://extensions.gnome.org/extension/1732/gtk-title-bar/ to always hide titles
- Pop Shell

However there's one thing missing: I was using the script which listens to notifications and runs .e.g.:
`wmctrl -r 'Telegram' -b add,demands_attention` when Telegram notification comes.

I'm kind of new to Gnome and what is feasible, so do you think it's possible to e.g. highlight a workspace (red background?) where a window needs attention (gets a notification)?

Thanks,
Nikita A