bug#21391: 24.5; `thing-at-point' should return a string

[Eli Zaretskii]

> Cc: 21391@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Fri, 11 Nov 2016 16:46:14 +0200
> 
> On 11.11.2016 16:35, Eli Zaretskii wrote:
> 
> >> The current implementation makes the things harder to understand.
> >> Currently one user need to read the source code to know the actual
> >> type this function returns.
> >
> > If that's a problem, let's improve the doc string (and the manual, if
> > needed) to make this more clear.
> 
> Improve how? By saying that the function behaves in a variety of ways, 
> solely depending on which `thing' it is passed?

Improve it by describing whatever it is that is evident from the code
that is not evident from the doc string.

> That won't make it much clearer, or make it easier to follow code that 
> uses `thing-at-point'.

I don't understand why.  It's not like we don't have other functions
that can return different kinds of objects.