Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r233648:
Remove trailing whitespace per mdoc lint warning

Approved by: cperciva (implicit)

MFC r235286:

General mdoc(7) and typo fixes.

PR: 167734

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

[mdoc] Fixed .Dt call.

Fix typos, spelling, formatting and mdoc mistakes found by Nobuyuki while
translating these manual pages. Minor corrections by me.

Submitted by: Nobuyuki Koganemaru <n-kogane@syd.odn.ne.jp>

Fix typos and spelling mistakes.

Bring in a SNMP module to support monitoring cloned wireless interfaces
via bsnmpd(1). The module implements a private BEGEMOT-WIRELESS-MIB.

Sponsored by: The FreeBSD Foundation
Reviewed by: philip@
Approved by: philip@