chore: add cargo fmt to the CI to ensure it is always checked

[szabgab]

Also add the rustfmt component to the ci

[kornelski]

Sorry, I don't want to reject PRs due to rustfmt.

It's unpleasant to get a build fail, PR blocked, and waste time manually push a fix for a nitpicky triviality that could be fixed anytime later.

rustfmt is IMO an architecturally flawed tool. It can make diffs larger (deletion of a single line can reformat a whole block), which makes reviewing harder. It makes a ton of poor choices due to having context-free formatting and no common sense, e.g. it won't keep all match arms use the same block or expression style if their line lengths cross different limits.

go fmt works way better by keeping the high-level layout choices from the input file, trusting people's common sense, and only fixes tedious stuff it understands.
rustfmt is built with the goal of complete destruction of the original formatting, expressing utter distrust of any human judgement, and I find that gross.

[szabgab]

I hear you. So do you run cargo fmt yourself and make that a separate commit?

[kornelski]

Yes, I occasionally run cargo fmt manually if I notice formatting that needs fixing. I wish there was a tool I could trust to format automatically, but rustfmt isn't it.