E0049 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/E0049.rs

Error E0049 needs a span_label, updating it from:

error[E0049]: method `foo` has 0 type parameters but its trait declaration has 1 type parameter
  --> src/test/compile-fail/E0049.rs:18:5
   |
18 |     fn foo(x: bool) -> Self { Bar } //~ ERROR E0049
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

To:

error[E0049]: method `foo` has 0 type parameters but its trait declaration has 1 type parameter
  --> src/test/compile-fail/E0049.rs:18:5
   |
18 |     fn foo(x: bool) -> Self { Bar } //~ ERROR E0049
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected 1 type parameter

Bonus: we may want to include the trait declaration is an additional span_label. This may require additional compiler work to make that span available.