bug#31349: 27.0; Doc of `up-list'

[Eli Zaretskii]

> Date: Wed, 2 May 2018 17:45:17 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> This is the description of the second new arg:
> 
>  If NO-SYNTAX-CROSSING is non-'nil' (as it is interactively), prefer to
>  break out of any enclosing string instead of moving to the start of
>  a list broken across multiple strings.  On error, location of point
>  is unspecified.
> 
> Looking at the code briefly, it seems to concern not only strings but
> also comments.  If so, shouldn't the description mention that?
> 
> At any rate, I don't follow the description.

I agree that the doc string could use some clarifications, especially
in the "prefer to break" part and the "list broken across multiple
strings" part.

Also, it seems there's a copy-paste error: both up-list and
backward-up-list talks about going to start of a list, whereas one of
them (up-list, AFAIU) should talk about end of a list.

> Why were these args added?

See this discussion:

  http://lists.gnu.org/archive/html/emacs-devel/2014-04/msg00110.html