I'm also not a fan of this phrase, which is whipped out to be "helpful" in reviews at my current employer--probably after the last time this website or one similar to it bubbled up on HN.
To be clear, the (American) dictionary definition of nit-picking is "minute and usually unjustified criticism." In other words, this is definitely not a positive thing to do, which is why this word has such strong negative connotations. Who wants to be nitpicked?
Nit-picking is not a "necessary" change, which is what makes it an exercise in finding the tiniest of fungus flies lurking in a proposed change. "I don't really want to think too hard about what you're proposing, or what your pull request contains, so here's a nit I noticed while examining the bike shed in front of your nuclear plant. #didmyjobboss"
I don't know what a trivial but necessary change is, but that's certainly not a minute criticism.
Au contraire: if I give you ten "nitpicks", the fact that it's "minute criticism" means that you explicitly have licence not to feel bad about it. I use the word "nitpick" in a review to induce the reaction of "sigh, I'll make your tiny change", possibly with "I-the-author don't care but apparently you-the-reviewer do for some reason" and "it's all Smaug123's fault for being unreasonable" if the author needs someone to blame mentally for the fact that the PR isn't approved immediately. It's an explicit label/reassurance that no important fault lies with the author.
This is very possibly a team culture thing, though. We all know that the code is what matters, and we are all studiously not letting our egos intervene, but we can help each other not get too attached by deflecting the blame onto the reviewer rather than the author in this tiny way.
To be clear, the (American) dictionary definition of nit-picking is "minute and usually unjustified criticism." In other words, this is definitely not a positive thing to do, which is why this word has such strong negative connotations. Who wants to be nitpicked?
Nit-picking is not a "necessary" change, which is what makes it an exercise in finding the tiniest of fungus flies lurking in a proposed change. "I don't really want to think too hard about what you're proposing, or what your pull request contains, so here's a nit I noticed while examining the bike shed in front of your nuclear plant. #didmyjobboss"
I don't know what a trivial but necessary change is, but that's certainly not a minute criticism.