Point to type argument span when used as trait

Given the following code:

```rust
struct Foo<T: Clone>(T);

use std::ops::Add;

impl<T: Clone, Add> Add for Foo<T> {
    type Output = usize;

    fn add(self, rhs: Self) -> Self::Output {
      unimplemented!();
    }
}
```

present the following output:

```nocode
error[E0404]: `Add` is not a trait
 --> file3.rs:5:21
  |
5 | impl<T: Clone, Add> Add for Okok<T> {
  |                ---  ^^^ expected trait, found type parameter
  |                |
  |                type parameter defined here
```

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