[temp.mem.enum] Fix consistency with [temp.inst]

The example is inconsistent with [temp.inst] p3, which states the following:
"The implicit instantiation of a class template specialization causes
 - the implicit instantiation of the declarations, but not of the definitions,
   of [...] scoped member enumerations [...]; and
 - the implicit instantiation of the definitions of [...]
   unscoped member enumerations [...]"

Hence, the example can be fixed by either (1) omitting the instantiation or
(2) by replacing the unscoped with a scoped enumeration.
Since the implicit instantiation does not contribute to the point of
[temp.mem.enum], the inconsistency can be solved most easily with alternative (1).

Note: The example was originally taken from DR1206.

Author: thebrandre

source/templates.tex

@@ -2659,7 +2659,6 @@
 template<class T> struct A {
   enum E : T;
 };
-A<int> a;
 template<class T> enum A<T>::E : T { e1, e2 };
 A<int>::E e = A<int>::e1;
 \end{codeblock}