code: public FessMessages addConstraintsDigitsMessage(String property, String fraction, String integer) {
          assertPropertyNotNull(property);
          add(property, new UserMessage(CONSTRAINTS_Digits_MESSAGE, fraction, integer));
          return this;
      }
docs: Add the created action message for the key 'constraints.Digits.message' with parameters.
  <pre>
  message: {item} is numeric value out of bounds (&lt;{integer} digits&gt;.&lt;{fraction} digits&gt; expected).
  </pre>
  @param property The property name for the message. (NotNull)
  @param fraction The parameter fraction for message. (NotNull)
  @param integer The parameter integer for message. (NotNull)
  @return this. (NotNull)