paragraph-start in Shell mode and Ielm.

[Luc Teirlinck]

I propose to change paragraph-start in Shell mode and Ielm from:

(setq paragraph-start comint-prompt-regexp)

to:

(setq paragraph-start (concat "[ \t\f]*$\\|" comint-prompt-regexp))

This will make no user visible difference, for reasons explained
below.  But the current value is misleading given the paragraph-start
docstring:

  *Regexp for beginning of a line that starts OR separates paragraphs.
  This regexp should match lines that separate paragraphs
  and should also match lines that start a paragraph
  (and are part of that paragraph).

In Shell mode and Ielm blank lines already do separate paragraphs,
since the value of paragraph separate is "[ \t\f]*$".  In view of the
above excerpt of the docstring, paragraph-start should match empty
lines too, which the current value does not.

I can install if desired.

Sincerely,

Luc.