Aliasing violation in `OrdSet` insertion

Inserting into an `im::OrdSet` (for example by collecting an iterator into one) can violate
Rust's aliasing rules: Miri reports a stacked borrows violation in
`sized_chunks::Chunk::force_copy()`, which is called during insertion, where a shared borrow
is invalidated by a unique borrow before the read through it completes.
This is undefined behavior, reachable from safe code.

No fixed version is available, as the crate is unmaintained; its GitHub
repository was archived by the owner on 2026-05-03.