Chilean voters head to the polls Sunday to choose a new leader to succeed outgoing President Sebastián Piñera. The two options before voters might have been unthinkable just a few years ago: A right-wing admirer of the late dictator Augusto Pinochet who has drawn comparisons to former President Donald Trump and Brazilian President Jair Bolsonaro, and a leftist former student leader who, at 35, could become Chile’s youngest president.