* src/process.c (Fmake_network_process): Add description of IPv6
address format.
The format of ADDRESS depends on the address family:
- An IPv4 address is represented as a vector of integers [A B C D P]
corresponding to numeric IP address A.B.C.D and port number P.
+- An IPv6 address has the same format as an IPv4 address but with 9
+elements rather than 5.
- A local address is represented as a string with the address in the
local address space.
- An "unsupported family" address is represented by a cons (F . AV)