Tracking issue for unstable option: format_generated_files. See [Processes.md, "Stabilising an Option"](https://github.com/rust-lang/rustfmt/blob/master/Processes.md#stabilising-an-option): * [ ] Is the default value correct? * [ ] The design and implementation of the option are sound and clean. * [ ] The option is well tested, both in unit tests and, optimally, in real usage. * [ ] There is no open bug about the option that prevents its use.