Undo/Redo History Position/Length Messages in redo.el

[Nordlöw]

Hi!

I believe it would be more convenient for the user to print the
position X and length N of the undo/redo-history along with the
current user feedback messages "Undo!" and "Redo!" in the package
redo.el. Examples:

- Undo!: [X/N]
- Redo!: [X/N]

where X/N is the Position/Length of the Undo-Redo-history.

I looked into the sources of redo.el but I can't figure out how to
extract X and N from all the lists: buffer-undo-list, pending-undo-
list.

Thanks in advance,
Nordlöw