Contribute Link on Businesses Page is broken

[sabine]

https://ocaml.org/industrial-users/businesses has a broken link to contribute.

[dinakajoy]

Hi @sabine This should link to https://github.com/ocaml/ocaml.org/blob/main/CONTRIBUTING.md right?

[sabine]

I think it should go to https://github.com/ocaml/ocaml.org/blob/main/CONTRIBUTING.md#add-an-academic-or-industrial-user, but it's a little weird that we have one section for both companies using OCaml (industrial user) and teaching institutions using OCaml (academic user). It would be better if we had dedicated sections because then we can explain more what to consider when adding information.

[dinakajoy]

@sabine
Please review #3021