bug#6576: documentation `string-to-char' is incorrect

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Magne Ingebrigtsen <larsi@gnus.org>
> Cc: schwab@linux-m68k.org,  monkey@sandpframing.com,  6576@debbugs.gnu.org
> Date: Thu, 14 Jul 2011 15:00:17 +0200
> 
> > Which other functions would need this?
> 
> `char-after', `aref' on a string, `following-char'...  Basically
> anything that returns a character.
> 
> >> Is there a specific reason this particular function deserves this
> >> detailed explanation?
> >
> > If you can suggest a better one that takes care of the original bug
> > report, please show your suggestion.
> 
> I think "close, notabug" would have taken care of the bug report.  :-)

The original problem which triggered the report was this part, and
this part only:

    A multibyte character is handled correctly.

To make a decent job for this bug, we need, as a minimum, to do
something with this unparsable sentence.  I admit that my suggestion
went well beyond that, but if we want to take a step back, please
suggest what to say instead.  I hope you agree that this sentence
cannot be left as-is.

(To know what is meant by this sentence, look at the source of the
function.)