8333599: Improve description of \b matcher in j.u.r.Pattern

Reviewed-by: smarks, alanb

Author: rgiulietti

src/java.base/share/classes/java/util/regex/Pattern.java

@@ -160,7 +160,7 @@
  *     <td headers="matches predef any">Any character (may or may not match <a href="#lt">line terminators</a>)</td></tr>
  * <tr><th style="vertical-align:top; font-weight:normal" id="digit">{@code \d}</th>
  *     <td headers="matches predef digit">A digit: {@code [0-9]} if <a href="#UNICODE_CHARACTER_CLASS">
- *  *         UNICODE_CHARACTER_CLASS</a> is not set. See <a href="#unicodesupport">Unicode Support</a>.</td></tr>
+ *          UNICODE_CHARACTER_CLASS</a> is not set. See <a href="#unicodesupport">Unicode Support</a>.</td></tr>
  * <tr><th style="vertical-align:top; font-weight:normal" id="non_digit">{@code \D}</th>
  *     <td headers="matches predef non_digit">A non-digit: {@code [^0-9]}</td></tr>
  * <tr><th style="vertical-align:top; font-weight:normal" id="horiz_white">{@code \h}</th>
@@ -251,8 +251,9 @@
  * <tr><th style="vertical-align:top; font-weight:normal" id="end_line">{@code $}</th>
  *     <td headers="matches bounds end_line">The end of a line</td></tr>
  * <tr><th style="vertical-align:top; font-weight:normal" id="word_boundary">{@code \b}</th>
- *     <td headers="matches bounds word_boundary">A word boundary: {@code (?:(?<=\w)(?=\W)|(?<=\W)(?=\w))} (the location
- *     where a non-word character abuts a word character)</td></tr>
+ *     <td headers="matches bounds word_boundary">A word boundary:
+ *     at the beginning or at the end of a line if a word character ({@code \w}) appears there;
+ *     or between a word ({@code \w}) and a non-word character ({@code \W}), in either order.</td></tr>
  * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_cluster_boundary">{@code \b{g}}</th>
  *     <td headers="matches bounds grapheme_cluster_boundary">A Unicode extended grapheme cluster boundary</td></tr>
  * <tr><th style="vertical-align:top; font-weight:normal" id="non_word_boundary">{@code \B}</th>