chore: use dprint to format the code

[aminya]

This fixes the inconsistent formatting in the code and the documentation via dprint

Before this, the documentation and code had inconsistent indentation that made the code hard to read. As an example:
https://lib.rs/crates/dot-generator

The commits are separated. The first commit adds the dprint config, and the second commit is fully automated and runs dprint fmt. No functional code changes have been made.

[besok]

Thanks. The library seems useful (although it states that it is under active development and the result can be unexpected ) but I am ready to give it a shot.

[aminya]

Thanks for the merge. It would be great if you regenerate the docs and release a new version!

[besok]

Indeed. Will do asap.