Fix documentation on swarm connect.

[timgws]

Issue #873.

A small change to get my feet wet and used to the code base. =)

[anarcat]

it's not clearer. it just adds "direct"! what does it mean? why is it useful? is it to bypass nats? what sort of connexion does it make? an http? TCP? which port? at least refering to something like external documentation might make this usage actually useful. :)

[whyrusleeping]

@anarcat it dials to a peer by a given multiaddr, the transport method is defined by the multiaddr. All it does is ensure that you have a connection to the peer in question.

The only other thing i can see adding would be some sort of link to multiaddr docs