debug: print assertion message upon failure (#1164)

src/entt/config/config.h

@@ -44,7 +44,7 @@
 #    define ENTT_ASSERT(condition, msg) (void(0))
 #elif !defined ENTT_ASSERT
 #    include <cassert>
-#    define ENTT_ASSERT(condition, msg) assert(condition)
+#    define ENTT_ASSERT(condition, msg) assert(condition && msg)
 #endif
 
 #ifdef ENTT_DISABLE_ASSERT