Rewrite wiki to en.wikipedia.org, avoid server bug.
<http://www.wikipedia.org/w/wiki.phtml?search=sue%20lawley>
incorrectly redirects to
<http://en.wikipedia.org/w/wiki.phtml?search=sue%2520lawley>
which searches for "sue%20lawley" rather than "sue lawley".
By using en.wikipedia.org directly, we avoid the server bug.
Prompted by an elinks-users post on 2007-07-27.
I asked on #wikimedia-tech, and www.wikipedia.org does always
redirect to en.wikipedia.org; it does not guess any other
language based on headers or IP addresses or such. Also, the
redirection exists only for compatibility, and skipping it
avoids a few roundtrips to the server. So this change is good
even if the server is eventually fixed.