[Enhancement request]: Exposing cursor position changes in callback

[domesticmouse]

It would be very useful to me to understand where a user's cursor is, both location in the content, and the pixel position, to enable giving syntax completion popups to the user.

It would also be useful to move the user's cursor, for example navigating to an error in the code being edited.

Any pointers on how to get started on implementing these features gladly accepted. Thanks!