added error handle for error code > 9999

Author: Kivooeo

compiler/rustc_error_codes/src/lib.rs

@@ -547,6 +547,7 @@ E0801: 0801,
 E0802: 0802,
 E0803: 0803,
 E0804: 0804,
+E9999: 9999,
         );
     )
 }

compiler/rustc_errors/src/codes.rs

@@ -7,7 +7,6 @@
 use std::fmt;
 
 rustc_index::newtype_index! {
-    #[max = 9999] // Because all error codes have four digits.
     #[orderable]
     #[encodable]
     #[debug_format = "ErrCode({})"]