SPOILER ALERT: This column contains spoilers for Season 3 of “Heartstopper,” now streaming on Netflix. The first two seasons of “Heartstopper,” Netflix’s popular YA series, were about falling in love. In Season 2 of “Heartstopper,” viewers watched the quiet and unsure Charlie Spring (Joe Locke) and his new boyfriend, the self-assured and protective Nick Nelson (Kit […]