E0069 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/E0069.rs

Error E0069 needs a span_label, updating it from:

error[E0069]: `return;` in a function whose return type is not `()`
  --> src/test/compile-fail/E0069.rs:12:5
   |
12 |     return; //~ ERROR E0069
   |     ^^^^^^

To:

error[E0069]: `return;` in a function whose return type is not `()`
  --> src/test/compile-fail/E0069.rs:12:5
   |
12 |     return; //~ ERROR E0069
   |     ^^^^^^ return type is not ()

[jaredwy]

This should land pretty soon (once i have confirmed the tests and have a compiling rustc)