Merge branch '6.4' into 7.2

* 6.4:
  [Validator] add pl translation for the Twig constraint
  dump default value for property hooks if present

Author: fabpot

Resources/translations/validators.pl.xlf

@@ -472,7 +472,7 @@
             </trans-unit>
             <trans-unit id="121">
                 <source>This value is not a valid Twig template.</source>
-                <target state="needs-translation">This value is not a valid Twig template.</target>
+                <target>Ta wartość nie jest prawidłowym szablonem Twig.</target>
             </trans-unit>
         </body>
     </file>