Ford and GM investors received a little insight when Stellantis announced its updated full-year guidance. Hint: It wasn't good. Say what you want about Stellantis (STLA 1.83%) and whether or not it should be included as a "Detroit automaker," but it still has a core Detroit SUV and truck business. And when one Detroit automaker issues a warning, others are certainly listening. Stellantis just served a major pessimistic warning that Ford Motor Company (F 1.15%) and General Motors (GM 1.56%) investors should ...