Update index.html

Update index.html for passed the xhtml 1.0 strict test http://validator.w3.org/check?uri=http%3A%2F%2Fsilentt.fr%2Fparkdar%2F&charset=%28detect+automatically%29&doctype=Inline&ss=1&group=0&user-agent=W3C_Validator%2F1.3+http%3A%2F%2Fvalidator.w3.org%2Fservices