Upgrade documentation after Jettison removal

asoldano@kikyo /dati/resteasy-master (master) $ fgrep -r jettison
docbook/reference/en/en-US/modules/Jaxb.xml:         <ulink url="https://github.com/jettison-json/jettison">https://github.com/jettison-json/jettison</ulink>.
docbook/reference/en/en-US/modules/Jaxb.xml:           To use this integration with Jettision you need to import the resteasy-jettison-provider Maven module.  Older versions
docbook/reference/en/en-US/modules/Jaxb.xml:at org.codehaus.jettison.mapped.MappedNamespaceConvention.getJSONNamespace(MappedNamespaceConvention.java:151)
docbook/reference/en/en-US/modules/Jaxb.xml:at org.codehaus.jettison.mapped.MappedNamespaceConvention.createKey(MappedNamespaceConvention.java:158)
docbook/reference/en/en-US/modules/Jaxb.xml:at org.codehaus.jettison.mapped.MappedXMLStreamWriter.writeStartElement(MappedXMLStreamWriter.java:241)