Item9693: Issues with statistics documentation

Clarify the documentation, and ensure that the examples are consistent.
Webs must be passed in using the -webs parameter.  An example showed it
being passed as a simple list of webs without the parameter name.

git-svn-id: http://svn.foswiki.org/branches/Release01x01/core@17199 0b4bb1d4-4e5a-0410-9cc4-b2b747904278