Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Small typo in the makedev(3) manpage.

devtoname(3) is a nonexistent function. We do have devtoname(9), but
that's entirely different. The correct function is devname(3).

Several documentation fixups related to device minor/major numbers:

- Document the minor(3), major(3) and makedev(3) macro's. They also
apply to umajor() and uminor() in the kernel, but hopefully we'll sort
that out one day.

- Briefly dev2unit() inside the make_dev(9) manual page, since this is
now the preferred macro to obtain character device unit numbers inside
the kernel.

- Remove the device_ids(9) manual page. It contains highly inaccurate
information, such as a description of the nonexistent major().