opam-related documentation is for general opam repository

[palmskog]

As per https://github.com/coq/opam?tab=readme-ov-file#opam-archive-for-coq the Coq opam archive has a specific layout and metadata requirements compared to the general opam repository. Nevertheless, the link on the right side of https://rocq-prover.org/packages goes to instructions about the general opam archive: https://opam.ocaml.org/doc/Packaging.html

There needs to be a page with Coq-specific opam packaging instructions that is linked to there instead, like https://coq.inria.fr/opam-packaging.html

[palmskog]

Maybe the following problem could be considered part of this issue as well: there are no instructions on how to add the released Coq opam repo, i.e., there is no place where users are told to do:

opam repo add coq-released https://coq.inria.fr/opam/released

before they install a Coq-related package.