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

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

Remove trailing whitespace per mdoc lint warning

Disussed with: gavin
No objection from: doc
Approved by: joel
MFC after: 3 days

Remove superfluous paragraph macro.

mdoc: consistently spell our email addresses <foo@FreeBSD.org>

Reviewed by: ru

- fix typos

PR: docs/125223
Submitted by: Fabian Keil <fk (a) fabiankeil.de>
MFC after: 3 days

Various mdoc style and wording fixes.

Reviewed by: ariff
MFC after: 3 days

Update snd_emu10kx driver with recent perforce changes (and few
other changes too).

(without any real order)

1. Use device_get_nameunit for mutex naming
2. Add timer for low-latency playback
3. Move most mixer controls from sysctls to mixer(8) controls.
This is a largest part of this patch.
4. Add analog/digital switch (as a temporary sysctl)
5. Get back support for low-bitrate playback (with help of (2))
6. Change locking for exclusive I/O. Writing to non-PTR register
is almost safe and does not need to be ordered with PTR operations.
7. Disable MIDI until we get it to detach properly and fix memory
managment problems.
8. Enable multichannel playback by default. It is as stable as
single-channel mode. Multichannel recording is still an
experimental feature.
9. Multichannel options can be changed by loader tunables.
10. Add a way to disable card from a loader tunable.
11. Add new PCI IDs.
12. Debugger settings are loader tunables now.
14. Remove some unused variables.
15. Mark pcm sub-devices MPSAFE.
16. Partially revert (bus_setup_intr -> snd_setup_intr) since it need
to be done independently

Submitted by: Yuriy Tsibizov (driver maintainer)
Approved by: re (bmah)

Spelling fixes.

Revise markup.

General cleanup, not quite finished yet.

Add a man-page for snd_emu10kx. Someone with man-fu should have a look
and improve it.

Submitted by: Yuriy Tsibizov <Yuriy.Tsibizov@gfk.ru> (minor mods by me)