docs/tor-doc-unix.html.en#using points at incorrect SOCKS instructions.

https://www.torproject.org/docs/tor-doc-unix.html.en#using points users at https://trac.torproject.org/projects/tor/wiki/doc/TorFAQ#SOCKSAndDNS, when it should send them to https://www.torproject.org/docs/faq#TBBSocksPort