Optimize regex validator

[benmccallum]

Probably no need to instantiate the regex if the value being null never means it gets executed.

[benmccallum]

Was just digging around with .NET 7's GeneratedRegex attribute and it's possible with the Func<T, Regex> overload to call the generated regex property which is pretty cool, but thought I'd point out a potential optimization here.

[JeremySkinner]

hi @benmccallum thanks for this, although it doesn't build at the moment. Could you add in this missing semicolon then I'll get this merged. Thanks!

[benmccallum]

Ha, I swear 99% of the time I edit a file for something small like this online in GitHub I miss something and it doesn't build 😆

🤞🏻 it's ok now. and no worries :)

[JeremySkinner]

Thanks!