bug#19129: 25.0.50; recenter-positions is missing a reference to move-to-window-line-top-bottom

[Drew Adams <drew.adams@oracle.com>]

> > In the case in point, I'm guessing you've filled the paragraphs of
> > the doc string, which wasn't really necessary, since the lines were
> > of reasonable length.
> 
> Yes, that's right, but I did it mistakenly because I thought it was
> forgotten and that filling a paragraph would be necessary to be in
> accordance to Elisp coding conventions.
> 
> Now I learned that even though emacs-lisp-docstring-fill-column is
> 65 an 80 column filling might be acceptable!

Uh, not really, IMHO.  80-column filling violates the spirit, if not
completely the letter, of the GNU Emacs coding conventions.

What you did, it sounds like (to me), is fix an additional bug: a
doc-string line that was too long.  I would say thank you (while
still letting you know what Eli said about gratuitous changes).
But I don't speak for Emacs Dev.

From (elisp) `Documentation Tips':

* Format the documentation string so that it fits in an Emacs window
  on an 80-column screen.  It is a good idea for most lines to be
                  ^^^^^^
  no wider than 60 characters.  The first line should not be wider
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  than 67 characters or it will look bad in the output of `apropos'.

  You can fill the text if that looks good.  Emacs Lisp mode fills
  documentation strings to the width specified by
  `emacs-lisp-docstring-fill-column'.  However, you can sometimes
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  make a documentation string much more readable by adjusting its
  line breaks with care.  Use blank lines between sections if the
  documentation string is long.

The default value of `emacs-lisp-docstring-fill-column' is 65.

80 is the absolute maximum for a line.  Anything longer than 60 is
to be avoided.  Longer than 65 (`emacs-lisp-docstring-fill-column')
should be justified with good reasons, specific to the particular
case at hand.

The part about filling by default but possibly manually adjusting
line breaks to make things more readable should, IMO, explicitly
call out that what is meant is that you can introduce line breaks
at columns **less** than `emacs-lisp-docstring-fill-column'.