refactor(datepicker): normalize variable naming
refactor(datepicker): normalize variable naming

Closes #5450

caoruiy/bootstrap,caoruiy/bootstrap,RobJacobs/bootstrap,angular-ui/bootstrap,benhalverson/bootstrap,icfantv/bootstrap,looker/bootstrap,benhalverson/bootstrap,Servoy/bootstrap,burlhock/bootstrap,fpipita/bootstrap,shootermv/bootstrap,BookingBug/bootstrap,infowrap/bootstrap,Foxandxss/bootstrap,292388900/bootstrap,Foxandxss/bootstrap,Servoy/bootstrap,mabi/bootstrap,looker/bootstrap,burlhock/bootstrap,angular-ui/bootstrap,vfiles/bootstrap,wesleycho/bootstrap,Kpler/bootstrap,RobJacobs/bootstrap,Kpler/bootstrap,christor/bootstrap,shootermv/bootstrap,benhalverson/bootstrap,292388900/bootstrap,fpipita/bootstrap,mabi/bootstrap,byronigoe/bootstrap,benhalverson/bootstrap,vfiles/bootstrap,BookingBug/bootstrap,infowrap/bootstrap,christor/bootstrap,wesleycho/bootstrap,icfantv/bootstrap,byronigoe/bootstrap