* Clear the Os macro, which is assumed gracefully at run-off time.
* Use quotes to reduce the long name description (Nd) to a single
argument.
* Use meaningful arguments to the -width option of the Bl macro.
* Mark rc.conf up with Xr instead of Pa so that it is obvious that
further help on that file is available.
* Explicitly indicate that mediaopt is a command modifier (Cm) of
the ifconfig(8) utility.
* Do not mark up half-duplex and full-duplex as arguments (Ar),
since they are allowed values for an argument.
* Fix various grammar and spelling mistakes.
e478a84473