I know Wonder Woman has died in canon before, but in which issue did this happen?
Neron kills Wonder Woman in Wonder Woman Vol 2 #124. She's not 'Uncle Ben dead' which means she can be resurrected later as the new Goddess of Truth
General Steppenwolf kills the Wonder Woman from Earth-2 in Earth 2, Vol 1
Artemis briefly takes over as Wonder Woman before being killed by the White Wizard in The Challenge of Artemis (Wonder Woman Vol 2. #92-100)
Circe kills her in War of the Gods Vol 1. #3
Circe kills Wonder Woman (again) in War of the Gods part 22; The Demon #17