Acknowledgements Section with names

We agreed on a proposal for an expanded Acknowledgements appendix 
section for the next draft.  This is part of the resolutions to the 
formal objections to publishing the WCAG3 First Public Working draft 
last January.

Here is that proposal with names.  Since we did not set up a way of 
tracking active participation in 2016 - 2020, there may be names I have 
overlooked just because I haven't seen something recently to trigger 
that memory.

Extended Acknowledgements Proposal 
<https://docs.google.com/document/d/1WUm57EqqghUL8LObKG8VSwKTj83-DLuNZlFaAkZQpbA/>