6943959: NumericShaper API doc doesn't describe ARABIC/EASTERN_ARABIC precedence

Reviewed-by: peytoia

src/share/classes/java/awt/font/NumericShaper.java

@@ -99,6 +99,37 @@ import java.util.Set;
  * values are specified, such as {@code NumericShaper.Range.BALINESE},
  * those ranges are ignored.
  *
+ * <p><b>Decimal Digits Precedence</b></p>
+ *
+ * <p>A Unicode range may have more than one set of decimal digits. If
+ * multiple decimal digits sets are specified for the same Unicode
+ * range, one of the sets will take precedence as follows.
+ *
+ * <table border=1 cellspacing=3 cellpadding=0 summary="NumericShaper constants precedence.">
+ *    <tr>
+ *       <th class="TableHeadingColor">Unicode Range</th>
+ *       <th class="TableHeadingColor"><code>NumericShaper</code> Constants</th>
+ *       <th class="TableHeadingColor">Precedence</th>
+ *    </tr>
+ *    <tr>
+ *       <td rowspan="2">Arabic</td>
+ *       <td>{@link NumericShaper#ARABIC NumericShaper.ARABIC}<br>
+ *           {@link NumericShaper#EASTERN_ARABIC NumericShaper.EASTERN_ARABIC}</td>
+ *       <td>{@link NumericShaper#EASTERN_ARABIC NumericShaper.EASTERN_ARABIC}</td>
+ *    </tr>
+ *    <tr>
+ *       <td>{@link NumericShaper.Range#ARABIC}<br>
+ *           {@link NumericShaper.Range#EASTERN_ARABIC}</td>
+ *       <td>{@link NumericShaper.Range#EASTERN_ARABIC}</td>
+ *    </tr>
+ *    <tr>
+ *       <td>Tai Tham</td>
+ *       <td>{@link NumericShaper.Range#TAI_THAM_HORA}<br>
+ *           {@link NumericShaper.Range#TAI_THAM_THAM}</td>
+ *       <td>{@link NumericShaper.Range#TAI_THAM_THAM}</td>
+ *    </tr>
+ * </table>
+ *
  * @since 1.4
  */