Collapse index into one commit

Previous HEAD was ec46b51, now on the `snapshot-2025-09-05` branch

More information about this change can be found [online] and on [this issue].

[online]: https://internals.rust-lang.org/t/cargos-crate-index-upcoming-squash-into-one-commit/8440
[this issue]: rust-lang/crates-io-cargo-teams#47

Author: bors