comint.el has just got to implement bash's history-preserve-point

[Dan Jacobson]

comint.el has just got to implement bash's:
   history-preserve-point (default: Off)
     If set to on, the history code attempts to place point at the
     same location on each history line retrieved with
     previous-history or next-history.

One would go nuts entering e.g.,
$ : mm 1 mmmmmmmmmmmm
$ : mm 2 mmmmmmmmmmmm
$ : mm 3 mmmmmmmmmmmm
without it. Hence I resubmit this request.