Outdated references to cleared appendix D

[beutlich]

The reference to appendix D seems outdated.

The contributors to this and to previous versions of this document are listed in appendix D.

The revision history is available in appendix D.

[HansOlsson]

As indicated in #3908 (comment) I believe the simplest solution is to just remove the appendix.

[henrikt-ma]

As indicated in #3908 (comment) I believe the simplest solution is to just remove the appendix.

Addressed in #3906.