Auto merge of #120375 - matthiaskrgr:rollup-ueakvms, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #117420 (Make `#![allow_internal_unstable(..)]` work with `stmt_expr_attributes`)
 - #117678 (Stabilize `slice_group_by`)
 - #119917 (Remove special-case handling of `vec.split_off(0)`)
 - #120117 (Update `std::io::Error::downcast` return type)
 - #120329 (RFC 3349 precursors)
 - #120339 (privacy: Refactor top-level visiting in `NamePrivacyVisitor`)
 - #120345 (Clippy subtree update)
 - #120360 (Don't fire `OPAQUE_HIDDEN_INFERRED_BOUND` on sized return of AFIT)
 - #120372 (Fix outdated comment on Box)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors