Ppx documentation improvements.
Ppx documentation improvements.

rneswold/lwt,mirage/lwt,mirage/lwt,c-cube/lwt,fdopen/lwt,rneswold/lwt,ocsigen/lwt,rneswold/lwt,ocsigen/lwt,rgrinberg/lwt,fdopen/lwt,rgrinberg/lwt,mfp/lwt,rgrinberg/lwt,rgrinberg/lwt,c-cube/lwt,ocsigen/lwt,mfp/lwt,c-cube/lwt