Comment E0222 instead of removing it

Author: GuillaumeGomez

src/librustc_typeck/diagnostics.rs

@@ -1556,6 +1556,8 @@ register_diagnostics! {
     E0219, // associated type defined in higher-ranked supertrait
     E0220, // associated type not found for type parameter
     E0221, // ambiguous associated type in bounds
+    //E0222, // Error code E0045 (variadic function must have C calling
+             // convention) duplicate
     E0223, // ambiguous associated type
     E0224, // at least one non-builtin train is required for an object type
     E0225, // only the builtin traits can be used as closure or object bounds