Docs changes - package docs and CHANGES.txt

Author: markharwood

lucene/CHANGES.txt

@@ -58,8 +58,14 @@ API Changes
 
 * LUCENE-9340: SimpleBindings#add(SortField) has been removed. (Alan Woodward)
 
+* LUCENE-9445: QueryParserBase.getRegexpQuery and newRegexpQuery now take a 
+  caseSensitive flag to allow new case insensitive matching option. (Mark Harwood)
+
 Improvements
 
+* LUCENE-9445: QueryParser syntax for regular expressions extended to support 
+  trailing i for case insensitive matching e.g. /.*Foo/i (Mark Harwood)
+
 * LUCENE-9370: RegExp query is no longer lenient about inappropriate backslashes and
   follows the Java Pattern policy for rejecting illegal syntax.  (Mark Harwood)
 

lucene/queryparser/src/java/org/apache/lucene/queryparser/classic/package-info.java

@@ -192,6 +192,9 @@
  * syntax is documented in the {@link org.apache.lucene.util.automaton.RegExp RegExp} class. For example to find documents containing "moat" or "boat":
  * 
  * <pre class="code">/[mb]oat/</pre>
+ * <p>Searches against indexed terms can be made case insensitive by adding an `i` to the regex as in this example:
+ * 
+ * <pre class="code">/.*MiXeDcAsE/i</pre>
  * <a id="N1009B"></a><a id="Fuzzy_Searches"></a>
  * <h3 class="boxed">Fuzzy Searches</h3>
  * <p>Lucene supports fuzzy searches based on Damerau-Levenshtein Distance. To do a fuzzy search use the tilde, "~", symbol at the end of a Single word Term. For example to search for a term similar in spelling to "roam" use the fuzzy search: