Mention that we do not support unix* return values in DialArgs.
Mention that we do not support unix* return values in DialArgs.

License: MIT
Signed-off-by: Hector Sanjuan <e6fb06210fafc02fd7479ddbed2d042cc3a5155e@hector.link>

jbenet/go-multiaddr-net,jbenet/go-multiaddr