fix link to Justin Lily's helper post

Author: dhellmann

docs/en/tips.rst

@@ -83,7 +83,7 @@ Automatically Run workon When Entering a Directory
 ==================================================
 
 `Justin Lily posted
-<http://justinlilly.com/blog/2009/mar/28/virtualenv-wrapper-helper/>`__
+<http://justinlilly.com/python/virtualenv_wrapper_helper.html>`__
 about some code he added to his shell environment to look at the
 directory each time he runs ``cd``.  If it finds a ``.venv`` file, it
 activates the environment named within.  On leaving that directory,