E0201 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/associated-item-duplicate-names-3.rs

Error E0201 needs a span_note replaced with a span_label and needs span_labels, updating this:

error[E0201]: duplicate definitions with name `Bar`:
  --> src/test/compile-fail/associated-item-duplicate-names-3.rs:23:5
   |
23 |     type Bar = u16; //~ ERROR duplicate definitions
   |     ^^^^^^^^^^^^^^^
   |
note: previous definition of `Bar` here
  --> src/test/compile-fail/associated-item-duplicate-names-3.rs:22:5
   |
22 |     type Bar = i16;
   |     ^^^^^^^^^^^^^^^

To:

error[E0201]: duplicate definitions with name `Bar`:
  --> src/test/compile-fail/associated-item-duplicate-names-3.rs:23:5
   |
22 |     type Bar = i16;
   |     --------------- first definition of `Bar`
23 |     type Bar = u16; //~ ERROR duplicate definitions
   |     ^^^^^^^^^^^^^^^ duplicate definition