[bugfix] Avoid an NPE in DocumentTypeImpl when #toString() is called
[bugfix] Avoid an NPE in DocumentTypeImpl when #toString() is called

ljo/exist,jensopetersen/exist,opax/exist,windauer/exist,joewiz/exist,hungerburg/exist,opax/exist,windauer/exist,joewiz/exist,ljo/exist,wolfgangmm/exist,adamretter/exist,lcahlander/exist,ljo/exist,ambs/exist,ljo/exist,RemiKoutcherawy/exist,ambs/exist,adamretter/exist,adamretter/exist,olvidalo/exist,eXist-db/exist,lcahlander/exist,eXist-db/exist,olvidalo/exist,ambs/exist,wshager/exist,jensopetersen/exist,joewiz/exist,ambs/exist,dizzzz/exist,eXist-db/exist,wolfgangmm/exist,adamretter/exist,hungerburg/exist,jensopetersen/exist,jensopetersen/exist,dizzzz/exist,dizzzz/exist,eXist-db/exist,windauer/exist,RemiKoutcherawy/exist,lcahlander/exist,hungerburg/exist,olvidalo/exist,wolfgangmm/exist,wshager/exist,lcahlander/exist,eXist-db/exist,ljo/exist,hungerburg/exist,adamretter/exist,hungerburg/exist,windauer/exist,wolfgangmm/exist,dizzzz/exist,olvidalo/exist,lcahlander/exist,eXist-db/exist,joewiz/exist,opax/exist,RemiKoutcherawy/exist,windauer/exist,RemiKoutcherawy/exist,joewiz/exist,olvidalo/exist,jensopetersen/exist,joewiz/exist,ambs/exist,wshager/exist,windauer/exist,wolfgangmm/exist,wolfgangmm/exist,ambs/exist,wshager/exist,wshager/exist,wshager/exist,opax/exist,dizzzz/exist,ljo/exist,lcahlander/exist,jensopetersen/exist,opax/exist,RemiKoutcherawy/exist,dizzzz/exist,adamretter/exist,RemiKoutcherawy/exist