E0252 needs to be updated to new format

[sophiajt]

From: src/test/compile-fail/double-import.rs

Error E0252 needs an updated unit test and span_labels, updating it from:

error[E0252]: a value named `foo` has already been imported in this module
  --> src/test/compile-fail/double-import.rs:25:5
   |
24 | use sub1::foo; //~ NOTE previous import of `foo` here
   |     --------- previous import of `foo` here
25 | use sub2::foo; //~ ERROR a value named `foo` has already been imported in this module [E0252]
   |     ^^^^^^^^^

error: requires `sized` lang_item

error: requires `sized` lang_item

error: requires `sized` lang_item

To:

error[E0252]: a value named `foo` has already been imported in this module
  --> src/test/compile-fail/double-import.rs:25:5
   |
24 | use sub1::foo; //~ NOTE previous import of `foo` here
   |     --------- previous import of `foo` here
25 | use sub2::foo; //~ ERROR a value named `foo` has already been imported in this module [E0252]
   |     ^^^^^^^^^ already imported

To remove the extra "error: requires sized lang_item", remove the:

#![feature(no_core)]
#![no_core]

Lines in the unit test.

[medzin]

I will do it.