preserve formatting and comments (toml_edit vs toml-rs)

Hi @samuelcolvin. Do you know if the [toml-rs](https://github.com/alexcrichton/toml-rs) library supports preservation of formatting and comments? Recently, I created a shared library wrapper around the rust `toml_edit` library (which does support comments and formatting, which was a requirement for my application of TOML). The library I built is called [toml-edit-labview](https://github.com/JKISoftware/toml-edit-labview/) since it's intended to be called from LabVIEW, but it builds the toml_edit rust library into a set of dll/so/dylib/.framework files for cross platform support). I was curious how this mapped into this (rtoml) project and your use case for TOML.