Fix comment on config_defaultTextClassifierPackage

    <!-- The package name for the default system textclassifier service.

         This service must be trusted, as it can be activated without explicit consent of the user.

         (e.g. com.android.textclassifier/.TextClassifierServiceImpl).

         Example: "com.android.textclassifier"

         If no textclassifier service with the specified name exists on the device (or if this is

         set to empty string), a default textclassifier will be loaded in the calling app's process.

         See android.view.textclassifier.TextClassificationManager.