update release notes wrt #242

Author: cowtowncoder

ion/src/main/java/com/fasterxml/jackson/dataformat/ion/IonGenerator.java

@@ -492,6 +492,9 @@ public void writeEndObject() throws IOException, JsonGenerationException {
         _writer.stepOut();
     }
 
+    /**
+     * @since 2.12.2
+     */
     public void writeEndSexp() throws IOException, JsonGenerationException {
         _writeContext = _writeContext.getParent();
         _writer.stepOut();
@@ -528,8 +531,11 @@ public void writeStartObject() throws IOException, JsonGenerationException {
         _writer.stepIn(IonType.STRUCT);
     }
 
+    /**
+     * @since 2.12.2
+     */
     public void writeStartSexp() throws IOException, JsonGenerationException {
-        _verifyValueWrite("start a sexp");                      // <-- copied from UTF8JsonGenerator
+        _verifyValueWrite("start a sexp");
         _writeContext = ((IonWriteContext) _writeContext).createChildSexpContext();
         _writer.stepIn(IonType.SEXP);
     }

release-notes/VERSION-2.x

@@ -16,6 +16,8 @@ Project: jackson-datatypes-binaryModules:
 #240: (cbor) Handle invalid CBOR content like `[ 0x84 ]` (incomplete array)
 #241: (ion) Respect `WRITE_ENUMS_USING_TO_STRING` in `EnumAsIonSymbolSerializer`
  (contributed by jhhladky@github)
+#242: (ion) Add support for generating IonSexps
+ (contributed by jhhladky@github)
 #244: (ion) Add support for deserializing IonTimestamps and IonBlobs
  (contributed by jessbrya-amzn@github)