Add docs for new validation features in .NET 11 Preview 5

[oroztocil]

Fixes #37183

[guardrex]

Thanks, @oroztocil ... I'll get this reviewed within a couple of hours.

I'll take care of the release notes if I can copy and cross-link to the content that you're placing here. It's best if I do that on the existing release notes PR to avoid a merge conflict with all of the other P5 release note items.

[oroztocil]

Thanks, @oroztocil ... I'll get this reviewed within a couple of hours.

I'll take care of the release notes if I can copy and cross-link to the content that you're placing here. It's best if I do that on the existing release notes PR to avoid a merge conflict with all of the other P5 release note items.

Thanks!

[guardrex]

@wadepickett @tdykstra ... Getting some OPS failures this morning on a couple of PRs, and closing/re-opening isn't working. I assume that they know about it. I'll give them some time and try again this afternoon.

[oroztocil]

There has been a lot of CI issues in aspnetcore as well. I can try pushing the "Re-run failed jobs" button.

[guardrex]

Thanks, @oroztocil ... I was hoping that this rebuild would succeed, but this one and my other PR hit another OPS 💥.

I'll check back this evening. Usually ... eventually 😄 ... the OPS comes back up.

We're looking good on coverage. I just need to add the release notes for the forms features to the other PR, and that won't take long. I'll probably do it this evening, but I could push that to tomorrow morning. Either way, we'll be ready for Preview 5 docs release. 👍

[oroztocil]

@guardrex Thank you! Let me know if I can help somehow 🙂