Implement {,} as an empty set literal

That is very true, some experimentation already took place regarding this: Frozenset literals and comprehensions

But it is least used among these as well. e.g. github:

  • /\blist\(/ - 13.2M
  • /\bset\(/ - 7.7M
  • /\bdict\(/ - 7.3M
  • /\btuple\(/ - 2.8M
  • /\bfrozenset\(/ - 0.5M

And given the first 4 have literals, their numbers are underestimated, while frozenset is close to final.