E0263 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/E0263.rs

E0263 needs a span_label, updating it from:

error[E0263]: lifetime name `'a` declared twice in the same scope
  --> src/test/compile-fail/E0263.rs:11:16
   |
11 | fn foo<'a, 'b, 'a>(x: &'a str, y: &'b str) { } //~ ERROR E0263
   |                ^^

To:

error[E0263]: lifetime name `'a` declared twice in the same scope
  --> src/test/compile-fail/E0263.rs:11:16
   |
11 | fn foo<'a, 'b, 'a>(x: &'a str, y: &'b str) { } //~ ERROR E0263
   |                ^^ declared twice

Bonus: underline and label the previous declaration:

error[E0263]: lifetime name `'a` declared twice in the same scope
  --> src/test/compile-fail/E0263.rs:11:16
   |
11 | fn foo<'a, 'b, 'a>(x: &'a str, y: &'b str) { } //~ ERROR E0263
   |        --      ^^ declared twice
   |        |
   |        previous declaration here

[Limeth]

I'm on it.