bug#49944: parse-partial-sexp fails to signal an error when (> START LIMIT).

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Tue, 10 Aug 2021 15:50:49 +0200
> Cc: 49944@debbugs.gnu.org, Stefan Monnier <monnier@iro.umontreal.ca>
> 
> Alan Mackenzie <acm@muc.de> writes:
> 
> > We definitely have a bug here.  The documentation in the elisp manual
> > says that the scanning is done "starting at START".  You're saying it's
> > perfectly OK to start scanning at "LIMIT"?  This violates the doc.
> 
> This is what all function like this say.  To take patient zero --
> narrow-to-region:
> 
> ---
> When calling from Lisp, pass two arguments START and END:
> positions (integers or markers) bounding the text that should
> remain visible.
> ---
> 
> Nothing here about allowing END to come before START, but it does allow
> that, and so do most (all?) similar commands.

Indeed, if the results are predictable, I see no reason not to support
START and END in any order, as we do in many places.