MFC r350969:
Add deprecation notice to snd_ds1(4).

As suggested in:
https://wiki.freebsd.org/WhatsGoing/FreeBSD13

We will be dropping the snd_ds1 driver. The driver is known to be buggy
and no one has been working on it for years now.
Users of old Yamaha cards may have luck with the OSS drivers instead.

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 (final part)

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

Make the SYNOPSIS section a bit more informative.

No one cares about when the manual page first appeared. Mention when the
driver appeared instead.

soundcard -> sound card

MFC after: 3 days

Remove superflous .Pp calls.

Submitted by: Joel Dahl <joel@automatvapen.se>
MFC after: 3 days

Update sound-related manpages to account for the recent change in
device and module naming. The following files were repo-copied:

csa.4 -> snd_csa.4
gusc.4 -> snd_gusc.4
maestro3.4 -> snd_maestro3.4
sbc.4 -> snd_sbc.4
uaudio.4 -> snd_uaudio.4

The pcm(4) manpage wasn't renamed to sound(4) as there are nearby
plans to rename "device sound" to "device snd", to address the
ambiguity in naming, so pcm.4 is linked to sound.4 for the moment.
(We also mumble something about the future plans in the manpage.)

Removed links from pcm.4 to als4000.4 and emu10k1.4 -- they now
have their own snd_*.4 manpages.

Fixes for recent snd_*.4 manpages: added missing "device sound"
to the SYNOPSIS, fixed hints (they are still "hint.pcm.<unit>"
in most cases).

MT5 after: 3 days

Add manual pages for several sound drivers.

Submitted by: Atte Peltomaki <koston@iki.fi>
Reviewed by: cg
MFC after: 5 days