Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

use .Mt to mark up email addresses consistently (part2)

PR: 191174
Submitted by: Franco Fichtner <franco@lastsummer.de>

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

- Grammar and typo fixes
- Rewording of some sentences

Reviewed by: brueffer
Approved by: emax (mentor)
MFC after: 3 days

Update bthidd(8) code and hook it up to the build.
bthidd(8) now was integrated with vkbd(4) and supports
multiple keyboards via vkbd(4)/kbdmux(4).

The code was tested with Apple Bluetooth keyboard and
SE k700i cell phone (remote control feature).

MFC after: 1 month