Undo unintended inlining of absl::void_t -- the inlining didn't actually replace it with std::void_t

PiperOrigin-RevId: 898825657
Change-Id: Icd97cec5602753759608623619acd7c6fd5bc953

Author: Abseil Team

absl/meta/type_traits.h

@@ -109,8 +109,7 @@ struct is_detected : is_detected_impl<void, Op, Args...>::type {};
 // appear duplicated (and thus invalid) to the compiler prior to substitution
 // taking place. Whenever possible, use `std::void_t` instead.
 template <typename... Ts>
-using void_t ABSL_REFACTOR_INLINE =
-    typename type_traits_internal::VoidTImpl<Ts...>::type;
+using void_t = typename type_traits_internal::VoidTImpl<Ts...>::type;
 
 // Historical note: Abseil once provided implementations of these type traits
 // for platforms that lacked full support. New code should prefer to use the