Fix headings

The intent in this doc is that the table defines headings which match up
with the major sections below it.  The "member" element got desynced in
a rename;  Resync it and add a title for "Active Contributor"

Change-Id: I60d6ae9ed73a7288fa6a0f8c7ba66a3076bbd9d1
Signed-off-by: Ed Tanous <etanous@nvidia.com>