Fix suggestion on DerefMut

[pickfire]

I tried this code:

fn t(n: &mut i32) {
    n = "42".parse().unwrap();
}

I expected to see this happen: Suggestion of *n = ..., the correct code would be

fn t(n: &mut i32) {
    *n = "42".parse().unwrap();
}

Instead, this happened: It did not look at mutable deref value and directly show the suggestion

error[E0277]: the trait bound `&mut i32: std::str::FromStr` is not satisfied
 --> src/lib.rs:2:14
  |
2 |     n = "42".parse().unwrap();
  |              ^^^^^ the trait `std::str::FromStr` is not implemented for `&mut i32`
  |
  = help: the following implementations were found:
            <i32 as std::str::FromStr>

Not sure why but I miss * quite often.

Meta

rustc --version --verbose:

1.42.0

[cuviper]

Closing as a duplicate -- #71389 has an updated edit and more labels applied.

[pickfire]

Oh weird, I didn't know github created the issue twice after I see the unicorn.