Fixes rakit/validation#130

Author: gdarko

src/Validation.php

@@ -509,7 +509,7 @@ protected function resolveRules($rules): array
             } else {
                 $ruleName = is_object($rule) ? get_class($rule) : gettype($rule);
                 $message = "Rule must be a string, Closure or '".Rule::class."' instance. ".$ruleName." given";
-                throw new \Exception();
+                throw new \Exception($message);
             }
 
             $resolvedRules[] = $validator;