(comint-prompt-regexp, comint-get-old-input)

(comint-prompt-regexp, comint-get-old-input)
(comint-use-prompt-regexp)
(comint-use-prompt-regexp-instead-of-fields)
(comint-replace-by-expanded-history, comint-send-input)
(comint-output-filter, comint-get-old-input-default)
(comint-line-beginning-position, comint-bol, comint-show-output)
(comint-backward-matching-input, comint-forward-matching-input)
(comint-next-prompt, comint-previous-prompt): Rename
`comint-use-prompt-regexp-instead-of-fields' to
`comint-use-prompt-regexp'.  Keep old name as alias and declare obsolete.
(comint-use-prompt-regexp): Shorten first line of doc string.