support negative counts about kakoune

[alexherbo2]

We have to consider this feature enables to remove alt- based commands used for opposite direction.

AFAIK we use alt to indicate alternate behaviour.

[davidaciko]

My vote is -, but Tab would also work nicely. I think n might cause problems with alternate keyboard layouts though (eg HJKL is HTNS on Dvorak).

[Delapouite]

closing explanation for posterity:

17:49:18      mawww | While the idea is seducing as it would allow for replacing all the
                    | backwards commands with just a `-<forward command>` its not really
                    | usable interactively, as its much easier to maintain <alt> down and to
                    | hit `n` a few times that do do -n-n-n-n