Add a default rustfmt to project root

[ishai1]

My attempt at a function which will create a default rustfmt file in the current project - following up on #68.

[CeleritasCelery]

Thanks for creating this PR. Why did you pick these particular settings for the rustfmt file?

[ishai1]

The default from copilot. At a quick glance it seemed reasonable but I don't have good insight in to what makes a good rustfmt config so won't pretend it's better than any other config.

[CeleritasCelery]

I don't think we would want to specify rustfmt settings for the user unless there is a de facto standard that most people would want. I would assume that the default settings (i.e. no rustfmt file) would be the most common.

[ishai1]

Fair enough, I think it could stil be nice to provide users with a basic rustfmt file. I changed to create a file with a single entry for edition which is defined to its default value of "2015" - https://rust-lang.github.io/rustfmt/?version=master&search=#edition.

I'll close the PR if it still doesn't seem appropriate to you 🙂.

[CeleritasCelery]

From the docs you linked:

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.

If we specify 2015 in the rustfmt toml file it will override what the user has in their cargo.toml. Which is probably not what user wants. Especially since that is a really old edition that realistically few people are using.

[ishai1]

Oh, good point! That is a pointer to how I should have solved this problem in the first place. Specifically changing rustic-rustfmt-bin to cargo and rustic-rustfmt-args to fmt will then pick up the version from cargo.toml.

[ishai1]

Thank you for the patient review! 🙂