[racket] unsubscribe

If you want to unsubscribe, please note the URL at the bottom of every
message to the list, as well as email headers that contain more
information on the list.

And related to this, I see many people who subscribe to both the
`users' list and the `announce' list -- the latter is used only for
announcements that are made to the former anyway, so there is no need
to subscribe to both.  I've clarified this on the web page.

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!