Address review comments

src/librustc_error_codes/error_codes/E0203.md

@@ -1,12 +1,18 @@
-Having multiple relaxed default bounds is unsuported.
+Having multiple relaxed default bounds is unsupported.
 
 Erroneous code example:
 
 ```compile_fail,E0203
-
-trait Foo {}
-
-struct S5<T>(*const T) where T: ?Foo + ?Sized;
+struct Bad<T: ?Sized + ?Send>{
+    inner: T
+}
 ```
 
-Here the type `T` cannot have a relaxed bound for both `Foo` and `Sized`
+Here the type `T` cannot have a relaxed bound for multiple default traits
+(`Sized` and `Send`). This can be fixed by only using one relaxed bound.
+
+```
+struct Good<T: ?Sized>{
+    inner: T
+}
+```