[Form] tweaked an exception message

src/Symfony/Component/Form/FormFactory.php

@@ -221,7 +221,7 @@ class FormFactory implements FormFactoryInterface
         while (null !== $type) {
             if ($type instanceof FormTypeInterface) {
                 if ($type->getName() == $type->getParent($options)) {
-                    throw new FormException(sprintf('The "%s" form type name ("%s") is not valid. It contains circullar reference to parent type name ("%s")', get_class($type), $type->getName(), $type->getParent($options)));
+                    throw new FormException(sprintf('The form type name "%s" for class "%s" cannot be the same as the parent type.', $type->getName(), get_class($type)));
                 }
 
                 $this->addType($type);