Set PdfString encoding to UTF-16 in PdfAnnotation#setContents(String) so that complex strings are encoded properly

Author: Snipx

kernel/src/main/java/com/itextpdf/kernel/pdf/annot/PdfAnnotation.java

@@ -43,6 +43,7 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.kernel.pdf.annot;
 
+import com.itextpdf.io.font.PdfEncodings;
 import com.itextpdf.kernel.color.Color;
 import com.itextpdf.kernel.geom.Rectangle;
 import com.itextpdf.kernel.pdf.PdfArray;
@@ -405,7 +406,7 @@ public PdfAnnotation setContents(PdfString contents) {
      * @return this {@link PdfAnnotation} instance.
      */
     public PdfAnnotation setContents(String contents) {
-        return setContents(new PdfString(contents));
+        return setContents(new PdfString(contents, PdfEncodings.UNICODE_BIG));
     }
 
     /**