E0516 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/E0516.rs

E0516 needs a span_label, updating it from:

error[E0516]: `typeof` is a reserved keyword but unimplemented
  --> src/test/compile-fail/E0516.rs:12:12
   |
12 |     let x: typeof(92) = 92; //~ ERROR E0516
   |            ^^^^^^^^^^

To:

error[E0516]: `typeof` is a reserved keyword but unimplemented
  --> src/test/compile-fail/E0516.rs:12:12
   |
12 |     let x: typeof(92) = 92; //~ ERROR E0516
   |            ^^^^^^^^^^ reserved keyword