MFC r331830:

Add deprecation notices for Arcnet and FDDI drivers.

We intend to remove support before FreeBSD 12 is branched.

Reviewed by: imp, emaste
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14890

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>

Work around an apparent mdoc(7) bug.

Spotted by: marius
Discussed with: ru

Break long lines and kill a few instances of EOL whitespace.

Noticed by: ru

Add a "Load module on start up" comment, similar to mac_*.4 pages[1].
Quote .Cd and .Nd text.
Bump doc date.

Requested by: some user through ru
Supported by: ru, dwmalone, brueffer

Scheduled mdoc(7) sweep.

Make the HARDWARE section better suited to the upcoming auto generated
Hardware Notes:

- Only include text related the device listings and hardware support
in the HARDWARE section.
- Make the HARDWARE section preamble text have a call to the Nm macro,
so the driver name will appear in the Hardware Notes.
- Add the manufacturer name to each item in the device list, where
appropriate.
- Clean trailing punctuation characters from the lists.

Help simon out and add a HARDWARE section.

Remove the ERRORS section in favor of a DIAGNOSTICS section.

Requested by: ru

Note that the implementation notes were not only derived from NetBSD but
also applies to other Arcnet drivers. Note that it should eventually
be moved to a more generic section.

Add manual pages for cm(4), esp(4), rc(4) and snc(4).