> Type inference has left academy and proliferated into mainstream languages for so many years that I almost forgot that it's a worth mentioning feature.

I'm not even sure I'd call this type inference (other people definitely do call it type inference) given that it's only working in one direction. Even Java (var) and C23 (auto), the two languages the author calls out, have that. It's much less convenient than something like Hindley-Milner.