Blazor InputRadio/Group components

[guardrex]

Fixes #19522

Internal Review Topic (links to Radio buttons section)

I'm not quite there locally for preview bits yet. I usually get on the new bits at RC1. This PR was derived from the engineering PR.

• InputRadio and InputRadioGroup component coverage.
• Standardizing the use of @ on submit methods.

[MackinnonBuck]

Looks great! Do you think we still need this section: https://github.com/dotnet/AspNetCore.Docs/pull/19555/files#diff-daa7e01c3897b91132b91d1ec06e7018R809, given there's now a first-party InputRadio solution? If you think we should leave it in for those using an older version of the framework, that sounds fine to me, just thought I'd check 😃

[guardrex]

@MackinnonBuck ... Yes, DR and Artak have advised in similar scenarios on other 5.0 PRs to keep the <5.0 approaches for the 3.x versions of the topics.

[guardrex]

@MackinnonBuck I think we can simplify manufacturer text that goes with the InputRadio components from ...

@foreach (var manufacturer in (Manufacturer[])Enum
    .GetValues(typeof(Manufacturer)))
{
    <InputRadio Value="manufacturer" />
    @manufacturer.ToString();
    <br>
}

... to ...

@foreach (var manufacturer in (Manufacturer[])Enum
    .GetValues(typeof(Manufacturer)))
{
    <InputRadio Value="manufacturer" />
    @manufacturer
    <br>
}

I put that update on the last commit. Seem ok to you?

[MackinnonBuck]

@guardrex Yep, looks good!