Hello,

I found a small bug in thingatpt.el. `beginning-op' for url's was using
an incorrect helper (end-of-thing) and changed it to the correct one.

This is my first time sending a patch to this list so I might be missing
something or doing something wrong wrt process.  If that's the case,
apologises in advance.  (My fsf papers are signed, so there's no problem
on that regard)

Cheers,

Raimon Grau