Definition of done: add copy spelling/grammar/pluralization

Since we don't all agree the pluralization is a given: https://github.com/barsoom/auctionet/commit/9d51c4b63be529bfd2f5f1ad7343fce78d010dc6#commitcomment-7958265

- [x] HN
- [x] TS
- [x] AR
- [ ] VA
- [x] KP
- [x] JK