doc: remove any mention of SOCKS4

SOCKS4 support was removed in 0127a9b, as well as the `-socks=` option.

contrib/debian/manpages/bitcoin-qt.1

@@ -32,10 +32,7 @@ Set database cache size in megabytes (default: 25)
 Specify connection timeout in milliseconds (default: 5000)
 .TP
 \fB\-proxy=\fR<ip:port>
-Connect through socks proxy
-.TP
-\fB\-socks=\fR<n>
-Select the version of socks proxy to use (4\-5, default: 5)
+Connect through SOCKS5 proxy
 .TP
 \fB\-tor=\fR<ip:port>
 Use proxy to reach tor hidden services (default: same as \fB\-proxy\fR)

contrib/debian/manpages/bitcoind.1

@@ -28,7 +28,7 @@ Start minimized
 Specify data directory
 .TP
 \fB\-proxy=\fR<ip:port>
-Connect through socks4 proxy
+Connect through SOCKS5 proxy
 .TP
 \fB\-addnode=\fR<ip>
 Add a node to connect to