Merge PR #305: cargo fix now removes extern crate

Author: traviscross

src/rust-2018/path-changes.md

@@ -67,9 +67,6 @@ and then there is no step two. If you're not using Cargo, you already had to pas
 `--extern` flags to give `rustc` the location of external crates, so you'd just
 keep doing what you were doing there as well.
 
-> One small note here: `cargo fix` will not currently automate this change. We may
-> have it do this for you in the future.
-
 #### An exception
 
 There's one exception to this rule, and that's the "sysroot" crates. These are the