massive refactor

Author: Christian Poveda

src/test/run-pass/closure_to_fn_coercion-expected-types.rs

@@ -7,7 +7,6 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-//
 // Ensure that we deduce expected argument types when a `fn()` type is expected (#41755)
 
 #![feature(closure_to_fn_coercion)]