A simple cargo fmt (a community auto formatter for Rust) results in around 3000 additions and less than 2000 deletions across 34 files.

rustfmt, which cargo uses for the fmt command, can be customized with a rustfmt.toml in the repository root which can contain 0 or more options listed here.

If formatting changes are to be kept to a minimum, custom formatting would need to be specified via a rustfmt.toml file. Otherwise, to go with the community standard, no file is needed, but all the roughly 5000 line changes would need to be applied.