WN: SignalR distributed tracing: Pre-work moving as is to include

[wadepickett]

Contributes to #33546

This is just the pre-work of moving the content as-is from the Product Unit into an include that is easier to diff from once I edit it.

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Internal previews

📄 File	🔗 Preview link
aspnetcore/release-notes/aspnetcore-9.0.md	What's new in ASP.NET Core 9.0

[wadepickett]

[Update: Please disregard, I went ahead and combined the two ActivitySource sections and will open a new PR after that for edits.]

BrennanConroy, this is just a prep for moving your original content to an include for the What's New before I do an edit and move inline code to a project and link it back in.

However, it looked like I should combine the new SignalR client ActivitySource and previous server ActivitySource into one section. I have not edited yet, basically just added those two sections under one parent section. Does that generally look OK? If so I will merge this, and then you will see a diff in the next PR for any edit changes I make if needed. Thanks.

[wadepickett]

I will go ahead and combine the two ActivitySource sections into one grouping and merge, then create a new PR to edit and move the code out to a project and link back in.

This PR was just prep only so we have something to diff against for edit.