input feedback

**Usecase:** Pupils get everithing right but one single transposition. It will now take a while to figure out what was wrong since they have to check everything.
**Suggestion:** Could the app return the pw until the first wrong letter und highlight this one in red, e.g. if was "ABCD...L" and I enter "ACBD...L" it should return "Wrong passoword: AC" where C ist highlighted in red?