Update javadoc to fix the build.

             add printers to this print service. -->

        <attr name="addPrintersActivity" format="string"/>

        <!-- Fully qualified class name of an activity with advanced print options

             specific to this print service. If this activity is specified the system

             will allow the user a choice to open it given the currently selected printer

             has advanced options which is specified by the print service via

             {@link android.print.PrinterInfo.Builder#setHasAdvancedOptions(boolean)}.

             -->

             specific to this print service. -->

        <attr name="advancedPrintOptionsActivity" format="string"/>

        <!-- The vendor name if this print service is vendor specific. -->

        <attr name="vendor" format="string"/>