chore: fix format with nightly

[elenaf9]

Description

Fix formatting with nightly.

Without nightly, some of our rustfmt.toml rules aren't applied because they are not stable yet (e.g. our group_imports rule).
Our CI didn't catch it yet because it doesn't check fmt on nightly. Will fix that in a follow-up PR.

Notes & open questions

Came up in #5725 (comment).

cc @drHuangMHT you were actually correct in #5726 (comment), the items are reordered across blocks because of our rule group_imports = "StdExternalCrate")

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[kamuik16]

Description

Fix formatting with nightly.

Without nightly, some of our rustfmt.toml rules aren't applied because they are not stable yet (e.g. our group_imports rule).
Our CI didn't catch it yet because it doesn't check fmt on nightly. Will fix that in a follow-up PR.

Notes & open questions

Came up in #5725 (comment).

cc @drHuangMHT you were actually correct in #5726 (comment), the items are reordered across blocks because of our rule group_imports = "StdExternalCrate")

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

Can we also fix the fmt workflow to use the nightly feature on the cargo fmt check?

[elenaf9]

Can we also fix the fmt workflow to use the nightly feature on the cargo fmt check?

Already opened #5743 :)

[jxs]

Thanks Elena!

cc @drHuangMHT you were actually correct in #5726 (comment), the items are reordered across blocks because of our rule group_imports = "StdExternalCrate")

Auch I didn't notice that, if you prefer we can switch to another option

[elenaf9]

HImm unfortunately there's no option that groups std/external/crate and private/ public, so I am okay with sticking with the current one.