Diagnostic Port and Microsoft.Diagnostics.NetCore.Client

[mikelle-rogers]

Documentation Request

Needs clarification/direction

Previous documentation

As mentioned in #515

[hoyosjs]

https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-environment-variables#dotnet_diagnosticports mentions dotnet-monitor as the sole consumer of the port and it does so in a way that can be interpreted incorrectly. When the port documentation is done, it'd be good to just say "This variable is used to specify how to configure EventPipe's IPC channels, and this is a full explanation of how it works."