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

[Dmitry Gutov]

On 11.11.2016 16:51, Eli Zaretskii wrote:

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

So we will enumerate how every built-in "thing" behaves? That still 
won't account for the third-party ones.

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

Because there is no rhyme or reason in the current behavior, no matter 
how you want to look at it.

E.g. symbols or sexps are not strings, and yet (thing-at-point 'symbol) 
and (thing-at-point 'sexp) return strings (or nil).