Auto merge of #119218 - Nadrieril:nested-opaque-reveal, r=compiler-errors

Exhaustiveness: Reveal empty opaques in depth

Follow-up to rust-lang/rust#116821. As noted [there](rust-lang/rust#116821 (comment)), the current implementation doesn't detect emptiness of opaques when the opaque is nested inside a type. This doesn't matter for stable behavior (which ignores nested empty types anyway) but does matter for the [`exhaustive_patterns`](https://github.com/rust-lang/rust/issues/51085)/[`min_exhaustive_patterns`](https://github.com/rust-lang/rust/pull/118803) features.

This PR fixes this behavior by adding `InhabitedPredicate::apply_reveal_opaque` that considers opaque types when determining inhabitedness.

r? `@compiler-errors`

Author: bors