[RC1] Doc Http/3 for Http.Sys

[Tratcher]

Fixes dotnet/aspnetcore#35204

Consider holding this update until RC1 releases.

[wtgodbe]

What about:

  <ItemGroup>
    <!-- Required for QUIC & HTTP/3 in .NET 6 - https://github.com/dotnet/runtime/pull/55332 -->
    <RuntimeHostConfigurationOption Include="System.Net.SocketsHttpHandler.Http3Support" Value="true" />
  </ItemGroup>

[Tratcher]

What about:

  <ItemGroup>
    <!-- Required for QUIC & HTTP/3 in .NET 6 - https://github.com/dotnet/runtime/pull/55332 -->
    <RuntimeHostConfigurationOption Include="System.Net.SocketsHttpHandler.Http3Support" Value="true" />
  </ItemGroup>

That's only required for HttpClient.

[Tratcher]

@Rick-Anderson the monikers need work. How should we handle them for 5.0 and 3.1?

[Rick-Anderson]

@Rick-Anderson the monikers need work. How should we handle them for 5.0 and 3.1?

I can fork this and fix them. You can review my PR and merge into this branch. OR, I could just create a new PR with them fixed and all the content you have here. Your call.

[Rick-Anderson]

Suggested change

	[HTTP/3](https://quicwg.org/base-drafts/draft-ietf-quic-http.html) is enabled for ASP.NET Core apps if the following base requirements are met:
	[HTTP/3](https://quicwg.org/base-drafts/draft-ietf-quic-http.html) is enabled for ASP.NET Core apps when the following base requirements are met:

[Rick-Anderson]

@Rick-Anderson the monikers need work. How should we handle them for 5.0 and 3.1?

I should probably make a RC1 branch and when this is finished, merge to RC1. At RC1, we can merge the RC1 branch into main.

[Tratcher]

@Rick-Anderson the monikers need work. How should we handle them for 5.0 and 3.1?

I can fork this and fix them. You can review my PR and merge into this branch. OR, I could just create a new PR with them fixed and all the content you have here. Your call.

Whatever's easier for you.

[Rick-Anderson]

@Tratcher I can always prepare the ::: moniker range=">= aspnetcore-6.0" section for you.

[Rick-Anderson]

moved to #23257