Improve Regex to deal with trailing characters in URLs

[dsgriffin]

For example, a click-through link to a StackOverflow question appends the extra chars ?rq=1, e.g.

http://stackoverflow.com/questions/24816/escaping-html-strings-with-jquery?rq=1

Putting the regular link in the Allowlist (http://stackoverflow.com/questions/24816/escaping-html-strings-with-jquery) does not cover cases like the above.