021604431c
internal: support `#[rustc_coinductive]` rust-lang/rust#100386 changed the trait solver so that `Sized` is treated as coinductive trait, just like auto traits. This is now controlled by the perma-unstable `#[rustc_coinductive]` attribute (rust-lang/rust#108033), which this PR adds support for. In practice, I don't think this matters much if at all. Currently we don't give chalk enough information so chalk cannot precisely (dis)prove `Sized` bounds.