Print HRTB binders before fn qualifiers Fixes rust-lang/rust#151393 This PR updates the custom fn-signature diff used in type mismatch diagnostics to print higher-ranked binders before fn qualifiers. We might want to update reference also: https://github.com/rust-lang/reference/blob/581920f9109f141b88b860b3e1e8359e3896a150/src/items/external-blocks.md?plain=1#L60