Fix #286 URL Regex Problem

Fix #286 URL Regex Problem
Looks good, but why did you remove the function body? Plugins may still use it.

I think it should handled like other deprecated functions, for example:
https://github.com/Sama34/mybb/blob/fix-286/inc/functions.php#L6632
So:
- the function itself should be not touched, only its calls removed
- deprecation notice should be in the first comment line so that it's clearly visible