I wouldn't say nitpicks are necessary changes in most circumstances - they are really soft suggestions about very fine details, I tend to describe them with opt

I wouldn't say nitpicks are necessary changes in most circumstances - they are really soft suggestions about very fine details, I tend to describe them with optional non-blocking comments. Nitpick is a really good term for them but "aesthetic" might work as an alternative, there isn't a huge glut of words in that realm though.