code: public FessMessages addConstraintsScriptAssertMessage(String property, String script) {
          assertPropertyNotNull(property);
          add(property, new UserMessage(CONSTRAINTS_ScriptAssert_MESSAGE, script));
          return this;
      }
docs: Add the created action message for the key 'constraints.ScriptAssert.message' with parameters.
  <pre>
  message: script expression "{script}" didn't evaluate to true.
  </pre>
  @param property The property name for the message. (NotNull)
  @param script The parameter script for message. (NotNull)
  @return this. (NotNull)