Mention /dev/vn0b and /dev/vntab.  ascii -> ASCII transform had already happened in an earlier commit.
Mention /dev/vn0b and /dev/vntab.  ascii -> ASCII transform had
already happened in an earlier commit.

PR:             docs/13645
Submitted by:   Stephen Roznowski <sjr@home.com>

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase