PDFBOX-5660: fix typo, as suggested by Valery Bokov; closes #438

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/branches/2.0@1932979 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDDocument.java

@@ -1418,7 +1418,7 @@ private void subsetDesignatedFonts() throws IOException
      * signed</a>. (PDFBox already does this for signature widget annotations)
      * <p>
      * Another problem with page-based modifications can occur if the page tree isn't flat: there
-     * won't be an closed update path from the catalog to the page. To fix this, add code like this:
+     * won't be a closed update path from the catalog to the page. To fix this, add code like this:
      * <pre>{@code
      * COSDictionary parent = page.getCOSObject().getCOSDictionary(COSName.PARENT);
      * while (parent != null)