Update BARE_TRAIT_OBJECT and ELLIPSIS_INCLUSIVE_RANGE_PATTERNS to errors in Rust 2021 This addresses https://github.com/rust-lang/rust/pull/81244 by updating two lints to errors in the Rust 2021 edition. r? `@estebank`
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.