:bug: Accepts invalid domains

[AlainODea]

• Broaden GENERIC lexer regex to include non-ASCII for IDNs

• Consider consecutive GENERIC tokens invalid in domain-part

• Consider a leading hyphen in any part of a domain name an error

Fix cover tests cases from #2 as well.

[egulias]

Thanks!

[AlainODea]

My pleasure, @egulias. This is an awesome library! Thank you for creating and maintaining it 😊

[egulias]

Much appreciated! Sadly I can't dedicate all the time I should. Happy to see more of your work, keep the PRs comming ;)!