First attempt at making an importing utility for Rust.

The goal is to get some sort of auto-importing to Rust.
Having a reliable way to add an import statement would greatly help with this.

• [ ] Preserve formatting (Discussion in #3)
• [ ] Sort imports
• [x] Actually make it work somewhat
• [x] Basic auto-importing
• [x] Group imports
• [x] Add missing extern crates

Abslutely not. This is not in a usable state yet.

I did have a plan to auto-import stuff, but I got multiple recommendations to leave that to the RLS.
Reddit thread

There is some basic auto importing with the -a option that asks Cargo what to import.