Can't link to higher rank function in docs

[pchiusano]

for instance {{ @signature{Scope.run} }} doesn't work. It's due to the fact that our type system doesn't do impredicative instantiation.

@runarorama suggested the following "hack"

Modify the render for Doc.Term - if it's Any (blah ; ()), just show that as blah. Maybe use special () type.

Pretty-printer would also have to detect this and reverse it.

[ceedubs]

This prevents me from using @signature for pretty much anything in ceedubs/exists 😬

[ceedubs]

Hmm but I notice that in the README for Scope if you hover over Scope.run it shows you the correct type signature. How is that being rendered? Can we reuse whatever it's doing for @signature?