[WIP] oxidoc: A (very early) command-line interface to Rust documentation

Hello. I'm used to using tools like ri for ruby to get documentation for libraries on the command line, but I found that in Rust you typically visit the documentation online. So, I decided to start a new project to access documentation for Rust code on the command line. This information could potentially be hooked into other interfaces like IDEs in the future.

A very early snapshot is available here: https://github.com/Ruin0x11/oxidoc. It allows the display of function signatures by name or by a fully qualified path like crate::module::function. Docstrings are absent because they are not included in Rust's AST at the moment, but that could be a future improvement.

I'm pretty new to Rust and creating/contributing to open source projects in general, so I would like to know any ways the code could be improved before everything else gets written. Contributions are highly welcome.

Many thanks to @brson and @alexcrichton for the early guidance.