Show other peoples' cursors

[bertob]

Multiple cursors would be helpful to be able to see where other people are typing, and who's typing what. A simple text cursor indicating their position with a random per-user color (and maybe an auto-generated animal name on hover?) would be a nice start.

There are two potential approaches for this:

1. insert a 1px wide widget as a character into the actual textview
2. get the coodinates and draw it as an overlay

• https://docs.gtk.org/gtk4/method.TextView.add_overlay.html
• https://docs.gtk.org/gtk4/method.TextView.get_iter_location.html
• https://docs.gtk.org/gtk4/method.TextView.window_to_buffer_coords.html