bug#20587: 24.1 forward-line docs inconsistent/surprising return value

[Eli Zaretskii]

> From: Eric Hanchrow <eric.hanchrow@gmail.com>
> Date: Sat, 23 May 2015 03:26:45 +0000
> 
> For what it's worth, my reaction was just the same as Vivek's:
> 
> * The behavior of forward-line surprised me;
> * The docstring describes that behavior, albeit without IMHO drawing 
> sufficient
> attention to its oddness;
> * The Elisp reference is clearly wrong.

I fixed the ELisp manual and tried to clarify in the doc string the
return value in this case.

Thanks.