Tooling: Formatter benchmark on unformatted projects

[MichaReiser]

Benchmark Ruff's formatter compatibility on unblacked projects by

• Format the project with Ruff
• Format the same project with Black
• Compare the outputs

[MichaReiser]

@konstin I believe you worked on this. Would you mind documenting your findings and closing the issue if there's nothing else to do?

[konstin]

I checked cpython and pretix and filed issues for cases black looks better for ruff format . && black .