update the manual about lwt.react
update the manual about lwt.react

Ignore-this: b6e0ecc17e9933dcc70b777ce55e3a58

darcs-hash:20110311095543-c41ad-da2fd7651d59732232cda88de9b33895701d6e5a.gz

avsm/lwt-OLD,avsm/lwt-OLD