Bug#780008: add working examples of exec-formatted to the man page

[積丹尼 Dan Jacobson <jidanni@jidanni.org>]

Package: xterm
Version: 314-1
Severity: wishlist
File: /usr/share/man/man1/xterm.1.gz

http://lukas.zapletalovi.com/2013/07/hidden-gems-of-xterm.html mentions
says

"Open URL
Best feature ever. I was waiting for this one for years. There
is new event called exec-formatted which allows you to execute arbitrary
commands. If you make a PRIMARY selection before that, you can open URLs
in browser easily."

but his example does not work.

Please add a working example to the official man page.