[ESS] A-M-r and A-M-s

[Richard M. Heiberger]

It looks like a typo.  It should be 
C-c M-s		comint-next-matching-input-from-input
C-c M-r		comint-previous-matching-input-from-input

Thanks for calling it to our attention.  I will fix it for the
next release.

Rich