Add links to original papers/discussions behind PS features

[chexxor]

I recently have become interested in the history of the "type class" concept. Wadler has a type classes page on his website which lists all the major type class-related papers he's been involved in. I later discovered that Mike Jones' "A System of Constructor Classes" paper is another key paper, but wasn't included in Wadler's list. I'm sure there are some details of some PS language features which are heavily influenced by some discussions on reddit or a haskell mailing list which would also be nice to reference.

There are several PS language features which have one or multiple well-considered papers, type classes being one. Any other language features other people can think of? Rank-N types? Surely there must be some academic papers referenced when implementing row/record types.

Anyways, we should cite and/or link to the papers/discussions inline with the feature docs in this repo. This sounds like a long-running task to fulfill, so I suggest we keep this issue around to collect suggestions or motivate people to submit PRs.

[chexxor]

Some sources of papers:

• https://wiki.haskell.org/Research_papers/Functional_pearls
• https://mitchellwrosen.github.io/haskell-papers/
• https://www.haskell.org/definition/from12to13.html

[hdgarrood]

https://discourse.purescript.org/t/academic-theoretical-basis-of-the-purescript-type-system/748/4 is looking pretty healthy now so I wonder if we should just link to that page from this repo?