just: Add just fmt

[tcharding]

We already have a just command to check the formatting, add one to run the formatter. Use the more terse just fmt although the difference from just format is not super obvious it is documented in the default output of just.

With this applied we have

$ just
Available recipes:
    build             # Cargo build everything.
    check             # Cargo check everything.
    default
    fmt               # Run cargo fmt
    format            # Check the formatting
    lint              # Lint everything.
    sane              # Quick and dirty CI useful for pre-push checks.
    update-lock-files # Update the recent and minimal lock files.

[coveralls]

Pull Request Test Coverage Report for Build 8640320775

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 83.127%

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Totals
Change from base Build 8629812825:	0.0%
Covered Lines:	19189
Relevant Lines:	23084

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💛 - Coveralls

[dpc]

If you can fix formatting, "checking formatting" is redundant. Might as well run format and see if there were any changes. In Fedimint we have just format doing formatting for Rust, Nix, and no one every asked for check-format.

[tcharding]

Yeah I thought the same, but its nice to be able to check it without making the changes:

• so one doesn't have to reset the changes
• if one has a dirty working directory and doesn't want to mix formatting changes in

[apoelstra]

If you can fix formatting, "checking formatting" is redundant

It's not. "Fixing formatting" is a destructive operation that affects an unpredictable number of files. Checking formatting is not.

[apoelstra]

ACK e565e06

[tcharding]

Candidate for merge now please, acked and open for over two weeks with no comments or nacks.