* memoize the `currentDisplayValue`
This used to be re-executed every single render. This should typically
not be an issue, but if you use non-deterministic code (E.g.:
`Math.random`, `Date.now`, …) then it could result in incorrect values.
Using `useMemo` allows us to only re-run it if the `data.value` or thte
`displayValue` actually changes.
* add test to verify `currentDisplayValue` is stable
* update changelog
Robin Malfait
000e0c0192