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

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

MFC r243079:
Add option to suppress just the plot in ministat while still retaining
the relative comparison (i.e., useful part).

Approved by: cperciva (implicit)

MFC r233648:
Remove trailing whitespace per mdoc lint warning

Approved by: cperciva (implicit)

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

Approved by: re (implicit)

Make the second example command more closely match the demo output, and as
a side effect more clearly show the change in command lines between the
first and second example invocations.

Fix apparent typo. The permitted confidence values include 95%, not 85%.

Pull ministat into the installed system and write it a man-page.

(Repocopied from src/tools/tools/ministat)