Typo in PropertySet::getXmlValue()

General JUCE discussion
1

There’s no default value to set or pass in:

        If the value isn't found in this set, then this will look for it in a fallback
        property set (if you've specified one with the setFallbackPropertySet() method),
        and if it can't find one there, it'll return the default value passed-in.

        @param keyName              the name of the property to retrieve
    */
    std::unique_ptr<XmlElement> getXmlValue (StringRef keyName) const;