Replace old private-in-public diagnostic with type privacy lints

Author: Bryanskiy

compiler/rustc_error_codes/src/error_codes.rs

@@ -607,6 +607,7 @@ E0794: include_str!("./error_codes/E0794.md"),
 //  E0420, // merged into 532
 //  E0421, // merged into 531
 //  E0427, // merged into 530
+//  E0445, // merged into 446 and type privacy lints
 //  E0456, // plugin `..` is not available for triple `..`
 //  E0465, // removed: merged with E0464
 //  E0467, // removed

compiler/rustc_error_codes/src/error_codes/E0445.md

@@ -1,10 +1,10 @@
-A private trait was used on a public type parameter bound.
+#### Note: this error code is no longer emitted by the compiler.
 
-Erroneous code examples:
+A private trait was used on a public type parameter bound.
 
-```compile_fail,E0445
-#![deny(private_in_public)]
+Previously erroneous code examples:
 
+```
 trait Foo {
     fn dummy(&self) { }
 }