Update javadoc

Signed-off-by: Andy Qin <[email protected]>

Author: q-andy

libs/core/src/main/java/org/opensearch/core/common/io/stream/StreamOutput.java

@@ -1257,7 +1257,7 @@ public <E extends Enum<E>> void writeEnumSet(EnumSet<E> enumSet) throws IOExcept
 
     /**
      * Writes an optional EnumSet with type E that by serialized it based on it's ordinal value
-     * For null enum set, writes false;
+     * For null or emptu enum set, writes false;
      */
     public <E extends Enum<E>> void writeOptionalEnumSet(@Nullable EnumSet<E> enumSet) throws IOException {
         if (enumSet != null && enumSet.size() > 0) {