Fixes#7099
This adds basic bell features to macOS to conceptually match the GTK
implementation. When a bell is triggered, macOS will do the following:
1. Bounce the dock icon once, if the app isn't already in focus.
2. Add a bell emoji (🔔) to the title of the surface that triggered
the bell. This emoji will be removed after the surface is focused
or a keyboard event if the surface is already focused. This
behavior matches iTerm2.
This doesn't add an icon badge because macOS's dockTitle.badgeLabel API
wasn't doing anything for me and I wasn't able to fully figure out
why...
macOS 12 is officially EOL by Apple and the project only supports
officially supported versions of macOS. Once publicly released, users on
older macOS versions will have to use older released builds.
