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)

Add an example Khelp module, which will be referenced in the forthcoming Khelp
documentation.

Sponsored by: FreeBSD Foundation
Discussed with: David Hayes <dahayes at swin edu au>
MFC after: 5 weeks
X-MFC with: r216615