Guidelines on giving/receiving code review comments

Central thesis here is that I think "please make this change" isn't "make this change or else". It should invite discussion if you feel strongly that it shouldn't happen.

Thoughts?
Clever code is mentioned explicitly elsewhere, but we could/should link to it.

https://github.com/sprintly/sprint.ly-culture/blob/master/Coding.mkd#pragmatism-over-novelty