Monad of no `return` Proposal (MRP): Moving `return` out of `Monad`

[David Luposchainsky]

A rename of neither pure nor return is going to happen.

- There is no known better name
- Renaming a popular class function eclipses any breaking change in its headache
potential (since the changes implied are highly non-local)
- Adding the name as a top-level synonym aliasing return aliasing return would
just grow the zoo of synonyms that we're trying to get rid of

Can we end the bikeshedding, or move this to a different discussion on the list?

Greetings,
David/quchen