w32-iconv: Remove invalid link to unicode.org in comment.
http://www.unicode.org/unicode/onlinedat/languages.html currently says:
The mapping information between Macintosh and Windows codes is no longer available on the Unicode site. Please consult the Macintosh and Windows developer sites.
And there are no outbound links.
- Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>