Cosmetic changes and doc improvements in obby/rudel-obby-client.el
* obby/rudel-obby-client.el
  (rudel-obby-client-state-session-synching::rudel-obby/net6_client_join):
  improved comment; cosmetic changes
  (rudel-obby/obby_document/sync_chunk): improved documentation
  string; changed let* -> let; use zerop instead of = ... 0; added a
  comment
  (rudel-obby-connection::rudel-publish): added a documentation string