Update tests for custom classes

tests/rustdoc-ui/feature-gate-custom_code_classes_in_docs.rs

@@ -12,7 +12,4 @@ pub struct Bar;
 /// ```ASN.1
 /// int main(void) { return 0; }
 /// ```
-//~^^^ WARNING custom classes in code blocks will change behaviour
-//~| NOTE see issue #79483 <https://github.com/rust-lang/rust/issues/79483>
-//~| HELP add `#![feature(custom_code_classes_in_docs)]` to the crate attributes to enable
 pub struct Bar2;