thing-at-point-url-at-point returns "incorrect" URL

[Christoph Scholtes]

Type something like the following in *scratch*:

"The GNU website (http://www.gnu.org) is a great resource for free
software."

Put point on the URL. 

M-: (thing-at-point-url-at-point) yields "http://www.gnu.org)".

I came across this while updating a link in one of the READMEs and used
(browse-url) to test the link.

Couldn thing-at-point-url-at-point handle this case smarter somehow,
e.g. by counting braces inside of the URL? In 99.999% of the cases this
URL will be invalid and we could DTRT.

Just wondering,
Christoph