Add outdated warning to old Haddock documentation that is among top search results on Google

[malteneuss]

Is it possible to add a warning to the old Haddock docs that those are outdated, and to add a link the latest docs? Or do an immediate redirect? It tripped me up (and others i know as well) in thinking this was the latest Markup syntax, because its links appear at the top of search results (at least on my machine):

As an alternative, we could try to demote its page rank somehow.

[tomjaguarpaw]

I agree that outdated documentation makes navigating the Haskell world treacherous. According to the work-in-progress PR to classify the subsites of haskell.org the Haddock subsite is owned by the Haddock maintainers. We should file an issue on the Haddock Github page to ask what they want to do (though please keep this issue open until we have a resolution). If you'd like to file it @malteneuss then please do, otherwise I'll do when I get round to it. I suspect the Haddock maintainers will want to

1. update that documentation to the latest version, or
2. insert a redirect to the latest version hosted elsewhere (if it is -- does anyone know)

[malteneuss]

@tomjaguarpaw i would be nice for you to file an issue as you seem to know the maintainers already.

[tomjaguarpaw]

Requested of the infra admins: haskell-infra/haskell-admins#7