make sure sort field updated when field deleted (#737)
make sure sort field updated when field deleted (#737)

holycrepe/anki,sunclx/anki,Arthaey/anki,xuewenfei/anki,ospalh/libanki3,jakesyl/ruby-card,socialpercon/anki-1,kenjhim/anki,weihautin/anki,jakesyl/ruby-card,abeyer/anki,florianjacob/anki,LucasCabello/anki,hssm/anki,hssm/anki,Stvad/anki,go38/anki,eduOS/anki,jkitching/anki,weihautin/anki,subfusc/anki