E0185 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/E0185.rs

E0185 needs a span_label, updating it from:

error[E0185]: method `foo` has a `&self` declaration in the impl, but not in the trait
  --> src/test/compile-fail/E0185.rs:18:5
   |
18 |     fn foo(&self) {} //~ ERROR E0185
   |     ^^^^^^^^^^^^^^^^

To:

error[E0185]: method `foo` has a `&self` declaration in the impl, but not in the trait
  --> src/test/compile-fail/E0185.rs:18:5
   |
18 |     fn foo(&self) {} //~ ERROR E0185
   |     ^^^^^^^^^^^^^^^^ `&self` not used in the trait

Bonus: show the trait that it's referencing.

error[E0185]: method `foo` has a `&self` declaration in the impl, but not in the trait
  --> src/test/compile-fail/E0185.rs:18:5
   |
12 |     fn foo();
   |     --------- trait declared without `&self`
...
18 |     fn foo(&self) {} //~ ERROR E0185
   |     ^^^^^^^^^^^^^^^^ `&self` used in impl

[yossi-k]

On it