E0458 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/E0458.rs

E0458 needs a span_label, updating it from:

error[E0458]: unknown kind: `wonderful_unicorn`
  --> src/test/compile-fail/E0458.rs:11:1
   |
11 | #[link(kind = "wonderful_unicorn")] extern {} //~ ERROR E0458
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

To:

error[E0458]: unknown kind: `wonderful_unicorn`
  --> src/test/compile-fail/E0458.rs:11:1
   |
11 | #[link(kind = "wonderful_unicorn")] extern {} //~ ERROR E0458
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unknown kind