fix: Support Nightly newer than nightly-2026-04-23

[polarathene]

• nightly-2026-04-24 => Fixed with printf-compat@0.4.0
• nightly-2026-05-30 => Fixed with unwinding@<unreleased>

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In April 2026 Nightly changes have introduced breaking changes that require printf-compat@0.4.0 to be compatible for compiling c-scape with.

Besides bumping the dependency version, there is a slight API change of .arg() to .next_arg().

[polarathene]

It seems another failure occurred since nightly-2026-05-30 with the unwinding crate (fixed 2 weeks ago) but waiting upon a new release: nbdd0121/unwinding#59

Since I'd prefer compatibility with latest Nightly, and nobody else has raised concerns with compatibility since April 2026 with c-scape or any of it's downstreams (c-gull => eyra/mustang)... I'll just leave this PR open until the unwinding crate has a new release that can be bumped in this PR.

[polarathene]

unwinding has published 0.2.9 👍 Tests should run with that without a manual bump AFAIK

[sunfishcode]

Thanks!