Remove Fn trait + impl Trait rustdoc tests

Author: chrisvittal

src/test/rustdoc/issue-43869.rs

@@ -55,10 +55,15 @@ pub fn test_44731_1() -> Result<Box<impl Clone>, ()> {
     Ok(Box::new(j()))
 }
 
-
-pub fn test_44731_3() -> Box<Fn() -> impl Clone> {
-    Box::new(|| 0u32)
-}
+// NOTE these involve Fn sugar, where impl Trait is disallowed for now, see issue #45994
+//
+//pub fn test_44731_2() -> Box<Fn(impl Clone)> {
+//    Box::new(|_: u32| {})
+//}
+//
+//pub fn test_44731_3() -> Box<Fn() -> impl Clone> {
+//    Box::new(|| 0u32)
+//}
 
 pub fn test_44731_4() -> Box<Iterator<Item=impl Clone>> {
     Box::new(g())
@@ -75,5 +80,4 @@ pub fn test_44731_4() -> Box<Iterator<Item=impl Clone>> {
 // @has issue_43869/fn.o.html
 // @has issue_43869/fn.test_44731_0.html
 // @has issue_43869/fn.test_44731_1.html
-// @has issue_43869/fn.test_44731_3.html
 // @has issue_43869/fn.test_44731_4.html