repl: fix preview cursor position

The cusor position was off in case the preview was exactly as long
as the current terminal was wide.

PR-URL: https://github.com/nodejs/node/pull/31293
Fixes: https://github.com/nodejs/node/issues/31291


Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>