config: provide coverage for user defined ENTT_ID_TYPE in the std namespace

src/entt/config/config.h

@@ -25,6 +25,8 @@
 #ifndef ENTT_ID_TYPE
 #    include <cstdint>
 #    define ENTT_ID_TYPE std::uint32_t
+#else
+#    include <cstdint> // provides coverage for types in the std namespace
 #endif
 
 #ifndef ENTT_SPARSE_PAGE