@Override
    public void processingInstruction(String target, String data) throws SAXException {
        warn("ProcessingInstruction: \u201C" + target + "\u201D, \u201C" + data + "\u201D.");
    }
@see nu.validator.checker.Checker#processingInstruction(java.lang.String, java.lang.String)
src/nu/validator/checker/DebugChecker.java