- It seems some browsers (Chrome and possibly others) will insert the
  credit card expiration month from autofill into the quantity input
  box, instead of the CC month.
- This causes the item's quantity to be set to "06" or whatever the CC
  expiry month was in autofill, causing all-around customer confusion!
- See:
  http://stackoverflow.com/questions/39937170/prevent-chrome-from-autofilling-creditcard-info
- To fix, we use an invalid value of autocomplete="nope" to prevent
  browsers from trying to autocomplete here, which some do even when
  autocomplete="off"
- With this, Chrome properly inserts the autofill into the CC month
  field.
- It's possible we could name our CC fields differently, per:
  https://developers.google.com/web/updates/2015/06/checkout-faster-with-autofill
  but at the moment, this fixes it.