commands: correct documentation of hg serve’s --ipv6 option When the --ipv6 option is given, the server doesn’t listen to a IPv4 socket. This can be verified by running two servers, one with and one without the option, which works fine. I think that listening to both a IPv4 and a IPv6 socket would be better, but given that the Python standard library class underlying the HTTP server supports only one socket, this is not trivial.