[libc++] Remove workarounds for [[nodebug]] not working properly on typedefs in older Clangs

Clang used to support [[nodebug]] everywhere except on typedefs. Since
we don't support such old Clangs anymore, we can get rid of _LIBCPP_NODEBUG_TYPE
in favour of always using _LIBCPP_NODEBUG.

Differential Revision: https://reviews.llvm.org/D108996

NOKEYCHECK=True
GitOrigin-RevId: 3557c7c1226fa222499a2b9d4cbc36dfeda6f53c
diff --git a/include/variant b/include/variant
index b0ea73d..2118c73 100644
--- a/include/variant
+++ b/include/variant
@@ -1196,11 +1196,11 @@
   template <class _Dest>
   static auto __test_impl(_Dest (&&)[1]) -> __identity<_Dest>;
   template <class _Dest, class _Source>
-  using _Apply _LIBCPP_NODEBUG_TYPE = decltype(__test_impl<_Dest>({declval<_Source>()}));
+  using _Apply _LIBCPP_NODEBUG = decltype(__test_impl<_Dest>({declval<_Source>()}));
 };
 
 template <class _Dest, class _Source>
-using __check_for_narrowing _LIBCPP_NODEBUG_TYPE =
+using __check_for_narrowing _LIBCPP_NODEBUG =
   typename _If<
 #ifdef _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT
     false &&
@@ -1244,11 +1244,11 @@
 template <size_t ..._Idx>
 struct __make_overloads_imp<__tuple_indices<_Idx...> > {
   template <class ..._Types>
-  using _Apply _LIBCPP_NODEBUG_TYPE = __all_overloads<__overload<_Types, _Idx>...>;
+  using _Apply _LIBCPP_NODEBUG = __all_overloads<__overload<_Types, _Idx>...>;
 };
 
 template <class ..._Types>
-using _MakeOverloads _LIBCPP_NODEBUG_TYPE = typename __make_overloads_imp<
+using _MakeOverloads _LIBCPP_NODEBUG = typename __make_overloads_imp<
     __make_indices_imp<sizeof...(_Types), 0> >::template _Apply<_Types...>;
 
 template <class _Tp, class... _Types>