Sublime::UrlDocument: don't (incorrectly) do a deep copy of the URL

This has been done incorrectly, converting all non-Latin characters
to '?'s. This effectively prohibits opening of files at non-Latin
pathes.

The original commit 9560e5 back in 2007 which introduced this "deep
copy" logic did not explain it in any way, so just do a normal copy.

REVIEW: 123218