- 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.
- 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
