Registration front-end notice for address formatting

One-sentence description

Show notice for address formatting on thalia registrations page in front end.

Why?

For international student from, i.e. Great-Britain, address formatting is weird. They put the house number in front. Now this produces an unclear error message.

Current implementation

An unclear error message

Suggested implementation

Either a clear error message (or example how you should format your address), or acceptance of more ways of formatting.