Fix capitalization
Most of our code uses camel case even for acronyms/initializms (but inconsistently). We should probably standardize on CAPITAL LETTERS, as advised in https://github.com/golang/go/wiki/CodeReviewComments#initialisms.
When making the change, please rename a single thing per commit so that if we change our mind it's easier to just exclude the commit. Also, don't refactor it all and then a single MR. Make 3-5 changes/commits and send an MR, then the next batch.
Edited by Mikhail Mazurskiy