It's weird to remember how, when Netflix launched, all of its series were very, very targeted to adult audiences. Now, in these post-Stranger Things days, it seems like nearly every other new series launching is tailored for teens — albeit much savvier, more adult teens than those in the pre-streaming days. And within that parameter is a fascinating range of tones, characters, and narratives, not to mention a real emphasis on diversity. From its beginnings, On My Block has been a standout example of this: Set in a rough area of Los Angeles, the series focuses on four …