Update constants.xml

Co-authored-by: Jordi Kroon <jordi@jordikroon.nl>

Author: lacatoire

reference/filter/constants.xml

@@ -167,7 +167,7 @@
      validation filter fails, instead of returning &false;.
     </simpara>
     <simpara>
-     Usable with any validation
+     Can be used with any validation
      <constant>FILTER_VALIDATE_<replaceable>*</replaceable></constant>
      filter.
     </simpara>