Invoice Number must be Alphanumeric - REOPEN

Feature requested

Quite a few of us use something like 20260504‑LF for an invoice reference

Typical use case

20260504LF is ok
20260504‑LF is not, but this is clearer.

The input validation on this box doesn’t make it clear that the dash is not allowed, it’s only when you click preview, after using 20260504‑LF several times, that you end up with an error.

1/ Please fix the input validation.
2/ Please allow dashes in invoice