Decl printing cleanup

[ChrisPenner]

Overview

Previously:

ability some.nested.Thing where theThing : Nat ->{some.nested.Thing} Int

Now:

ability some.nested.Thing where
  theThing : Nat ->{Thing} Int

Implementation notes

• Remove the PPE modifier for printing Decls which forces the FQN for all self-references. I believe it's no longer necessary now that the parser can look up constructors/abilities by suffix.
  • If there's an ambiguity the suffixifier will kick in and disambiguate just like it does everywhere else.
• Force a newline after where in GADTs, it looks awkward without it.

Test coverage

• I round-tripped base.
• Tested situations where multiple abilities had the same suffix; the pretty-printer still disambiguates as expected.

Loose ends

• Deploy this to share

[aryairani]

@mitchellwrosen Any thoughts on this?

Remove the PPE modifier for printing Decls which forces the FQN for all self-references. I believe it's no longer necessary now that the parser can look up constructors/abilities by suffix.