Merge riastradh-drm2 to HEAD.

Use Mt for email addresses.

branches: 1.12.2; 1.12.4;
- Remove redundant argument to (successive) `.Nm' macro;
- copy exact line from root's crontab(5) file (and the user name
is indeed unneeded, as root's crontab(5) file is not the system's
one);
- reword the warning: cron(8) _is_ running, by default.

From patch by Bug Hunting.

While here, remove xref to itself.

branches: 1.11.56;
Formatting improvements, sort SEE ALSO and sections.

fix up various .Nm abuses:
- keep the case consistent between the actual name and what's referenced.
e.g, if it's `foo', don't use '.Nm Foo' at the start of a sentence.
- remove unnecessary `.Nm foo' after the first occurrence (except for
using `.Nm ""' if there's stuff following, or for the 2nd and so on
occurrences in a SYNOPSIS
- use Sx, Ic, Li, Em, Sq, and Xr as appropriate

remove extra period in SEE ALL section

Merge in changes from OpenBSD.

fix typo

branches: 1.6.2;
- Fix .Nm usage.
- Sort SEE ALSO list first by section.

fix typos per pr-3349 submitted by SAITOH Masanobu

RCS id police.

Misc manpages fixes (PR #551)

Fix spelling error in Copyright notice

add at, by Thomas Koenig, ig25@rz.uni-karlsruhe.de