[docs] unicode in 3.1

u'Hello World !' from page http://docs.python.org/tutorial/introduction.html#unicode-strings does not work. Python 3.1, windows xp. probably cause http://docs.python.org/release/3.0.1/whatsnew/3.0.html , "3.1.3. Unicode Strings" part. Maybe you can add link to release page in tutorial, if not updating it. BR,