Remove dedicated string machine in the XML lexer.
Remove dedicated string machine in the XML lexer.

This removes the need for another fcall/fret combination.

altmetric/oga,dfockler/oga,jeffreybaird/oga,jeffreybaird/oga,dfockler/oga,altmetric/oga,dfockler/oga,jeffreybaird/oga,dfockler/oga,ttasanen/oga,jeffreybaird/oga,altmetric/oga,dfockler/oga,jeffreybaird/oga,YorickPeterse/oga,ttasanen/oga,altmetric/oga,altmetric/oga,YorickPeterse/oga,YorickPeterse/oga,ttasanen/oga,YorickPeterse/oga,YorickPeterse/oga,ttasanen/oga,ttasanen/oga