Add Built-in ASP.NET Core event source providers to docs

### Describe the issue or suggestion

We don't currently document the ASP.NET Core event sources.

https://learn.microsoft.com/en-us/dotnet/core/diagnostics/well-known-event-providers#aspnet-core

Hosting:

https://github.com/dotnet/aspnetcore/blob/a0652e0852f1dc9ea199a453efd421f6dfc04f1b/src/Hosting/Hosting/src/Internal/HostingEventSource.cs

`Microsoft.AspNetCore.Hosting`

Kestrel:

https://github.com/dotnet/aspnetcore/blob/a0652e0852f1dc9ea199a453efd421f6dfc04f1b/src/Servers/Kestrel/Core/src/Internal/Infrastructure/KestrelEventSource.cs

`Microsoft-AspNetCore-Server-Kestrel`

cc @noahfalk @samsp-msft

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#### Document Details

⚠ *Do not edit this section. It is required for learn.microsoft.com ➟ GitHub issue linking.*

* ID: d450dca8-b1fe-000d-4be4-898bfdb45e26
* Version Independent ID: 777accae-c5e7-1e92-756a-38fab9a23c33
* Content: [Well-known event providers in .NET - .NET](https://learn.microsoft.com/en-us/dotnet/core/diagnostics/well-known-event-providers#aspnet-core)
* Content Source: [docs/core/diagnostics/well-known-event-providers.md](https://github.com/dotnet/docs/blob/main/docs/core/diagnostics/well-known-event-providers.md)
* Service: **dotnet-fundamentals**
* GitHub Login: @tommcdon
* Microsoft Alias: **tommcdon**