Update edition in rustfmt.toml

[xFrednet]

I noticed that our rustfmt.toml still has the edition 2018 listed. This updates the configuration to use 2021.

This luckily doesn't introduce any formatting changes 🙃

changelog: none

[rust-highfive]

r? @giraffate

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[giraffate]

FYI: https://github.com/rust-lang/rustfmt#rusts-editions

Rustfmt is able to pick up the edition used by reading the Cargo.toml file if executed through the Cargo's formatting tool cargo fmt. Otherwise, the edition needs to be specified in rustfmt.toml, e.g., with edition = "2018".

[giraffate]

@bors r+

Thanks!

[bors]

📌 Commit acddac4 has been approved by giraffate

[bors]

⌛ Testing commit acddac4 with merge 8d12cd4...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: giraffate
Pushing 8d12cd4 to master...

[xFrednet]

FYI: https://github.com/rust-lang/rustfmt#rusts-editions

Rustfmt is able to pick up the edition used by reading the Cargo.toml file if executed through the Cargo's formatting tool cargo fmt. Otherwise, the edition needs to be specified in rustfmt.toml, e.g., with edition = "2018".

I also found that when I looked up what the configuration actually does. I'm guessing that the value was or is needed for the rust repo as that doesn't use cargo. That's just a guess, though 🙃. Thanks for the review