Correct long error message according to reviews

src/librustc_error_codes/error_codes/E0226.md

@@ -1,8 +1,8 @@
-Only a single explicit lifetime bound is permitted on trait objects.
+More than one explicit lifetime bound was used on a trait object.
 
 Example of erroneous code:
 
-```compile_fail
+```compile_fail,E0226
 trait Foo {}
 
 type T<'a, 'b> = dyn Foo + 'a + 'b; // error: Trait object `arg` has two
@@ -11,6 +11,7 @@ type T<'a, 'b> = dyn Foo + 'a + 'b; // error: Trait object `arg` has two
 
 Here `T` is a trait object with two explicit lifetime bounds, 'a and 'b.
 
+Only a single explicit lifetime bound is permitted on trait objects.
 To fix this error, consider removing one of the lifetime bounds:
 
 ```