Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

mdoc: move CAVEATS, BUGS and SECURITY CONSIDERATIONS sections to the
bottom of the manpages and order them consistently.

GNU groff doesn't care about the ordering, and doesn't even mention
CAVEATS and SECURITY CONSIDERATIONS as common sections and where to put
them.

Found by: mdocml lint run
Reviewed by: ru

Markup fixes.

Fixed the .Os call (missing or wrong).

Mechanically kill hard sentence breaks and double whitespaces.

Always start new sentences on a new line.

Submitted by: Anil Madhavapeddy <anil@recoil.org>

The man page for the new IDT77252 driver.