Style guide: mandating comments for literal arguments

Yoz,

I’ve reached a breaking point with both asking people to comment literals passed as arguments to functions, and being told what the comment form for bool constants should be, so I think it’s quite important we standardize (and mandates some of) these comments, so I’m proposing a change to the style guide.

The biggest goal of the proposed addition is basically mandating that endTxn(false) be typed as endTxn(false /* commit */).

I hope that this goal is not controversial. Assuming that proves to be true, I’m interested in bikeshedding the details and see if anybody wants to contribute anything.

https://github.com/cockroachdb/cockroach/pull/19185