Adapt to https://github.com/coq/coq/pull/19530

[proux01]

Adapt to coq/coq#19530
This is an adaptation in anticipation of the day the temporary backward compatibility introduced in the upstream PR will be removed (probably a few years in the future).
Merging this is not required for the upstream PR, you can do whatever you want with it.

[liyishuai]

As mentioned in #10 (comment), changes to the textbook first get merged into a private source repo, and then compiles to here.

Please acknowledge the following copyright transfer, and send an email to @bcpierce00.

sf/lf-current/Preface.v

Lines 452 to 491 in 43b800e

	(* ################################################################# *)
	(** * Note for Instructors and Contributors *)
	(** If you plan to use these materials in your own teaching, or if you
	are using software foundations for self study and are finding
	things you'd like to help add or improve, your contributions are
	welcome! You are warmly invited to join the private SF git repo.
	In order to keep the legalities simple and to have a single point
	of responsibility in case the need should ever arise to adjust the
	license terms, sublicense, etc., we ask all contributors (i.e.,
	everyone with access to the developers' repository) to assign
	copyright in their contributions to the appropriate "author of
	record," as follows:
	- I hereby assign copyright in my past and future contributions
	to the Software Foundations project to the Author of Record of
	each volume or component, to be licensed under the same terms
	as the rest of Software Foundations. I understand that, at
	present, the Authors of Record are as follows: For Volumes 1
	and 2, known until 2016 as "Software Foundations" and from
	2016 as (respectively) "Logical Foundations" and "Programming
	Foundations," and for Volume 4, "QuickChick: Property-Based
	Testing in Coq," the Author of Record is Benjamin C. Pierce.
	For Volume 3, "Verified Functional Algorithms," and volume 5,
	"Verifiable C," the Author of Record is Andrew W. Appel. For
	Volume 6, "Separation Logic Foundations," the author of record
	is Arthur Chargueraud. For components outside of designated
	volumes (e.g., typesetting and grading tools and other
	software infrastructure), the Author of Record is Benjamin
	Pierce.
	To get started, please send an email to Benjamin Pierce,
	describing yourself and how you plan to use the materials and
	including (1) the above copyright transfer text and (2) your
	github username.
	We'll set you up with access to the git repository and developers'
	mailing lists. In the repository you'll find the files
	[INSTRUCTORS] and [CONTRIBUTING] with further instructions. *)

[proux01]

@liyishuai the policy of Coq CI is that the repo/branch in there should accept overlay PRs. Do you confirm that such PRs should instead go to another repo (which one?), in that case, we should at the very least mention this in https://github.com/coq/coq/blob/718eabc3e8a6ad877ca875fa6647b931b5ffadd4/dev/ci/ci-basic-overlay.sh#L456-L457

[liyishuai]

Yes, this repo is a compilation result, rather than a "source code".

@bcpierce00 Do you feel like handling this PR and editing the documentation for Coq CI?