Reserve a home for List, Unit, Tuple2 (looking forward to `NoListTuplePuns`)

This would require some coordination with the Core Libraries Committee, but we could allocate a standard module that provides the type constructors required by [`NoListTuplePuns`](https://downloads.haskell.org/ghc/latest/docs/users_guide/exts/data_kinds.html#unique-syntax-for-type-level-lists-and-tuples).

I'm not saying the report should mention `NoListTuplePuns` language extension at all, merely mention the alternative way to specify types of lists and tuples and add the new module to the appendix. This would standardize a coding style forward-compatible with future Dependent Haskell.

Right now, this style would require `import Prelude.Experimental` or `import Data.Tuple.Experimental` which are obviously not meant to be permanent. So we'd have to reach out to CLC for a better module name.

Start with the report passages covering NoListTuplePuns and the appendix, then inspect the references to Prelude.Experimental and Data.Tuple.Experimental. Confirm the alternative list and tuple type syntax and coordinate the unresolved standard-module name with the Core Libraries Committee; done means the report documents the alternative and lists the agreed module.

Written by the indexing model from the issue text.