fix: allow fixing of trivial errors

[matthiaskrgr]

fn main() {
    let a = String::from("hello");
    print(a);
}

fn print(input: &str) {
	println!("{}", input);
}

error[E0308]: mismatched types
 --> src/main.rs:3:11
  |
3 |     print(a);
  |           ^
  |           |
  |           expected &str, found struct `std::string::String`
  |           help: consider borrowing here: `&a`
  |
  = note: expected type `&str`
             found type `std::string::String`
error: aborting due to previous error

The correct fix is already suggested, it would be great if cargo fix could apply that to the codebase.

cargo 1.29.0-nightly (2cd36b4ed 2018-07-25)

[dwijnand]

Duplicate of #5846

[alexcrichton]

Indeed!