Dart formatter vs rustfmt

Dart formatter has no write-up on Specifiction yet; its figures are above.

rustfmt formats Rust code according to style guidelines. It can format files directly or read code from standard input and write formatted output to standard output. With Cargo, `cargo fmt` formats binary and library targets in a crate and works with workspaces. A `rustfmt.toml` or `.rustfmt.toml` file can hold configuration, including stable and nightly-only options. For automated checks, `--check` returns code 0 when no formatting changes are needed and code 1 when changes would be made; it can be used in CI to fail a build on formatting differences. The README lists editor use with Vim, Emacs, Sublime Text 3, Atom, Visual Studio Code, IntelliJ, and CLion. Rustfmt is available on Windows, macOS, and Linux, and is distributed under the MIT License and Apache License 2.0. It does not attempt to format comments, and listed limitations also involve macros, unparsable code, fragments, and non-ASCII Unicode. Unstable settings require opt-in on nightly, and the README says the latest version requires the nightly toolchain.