Describe ConfigureAwait(false) case

WRT: https://github.com/dotnet/dotnet-api-docs/blob/main/xml/System.Threading.Tasks/Task.xml

Everyone uses `ConfigureAwait(false)` but the docs only mentions the true case and it's quite hard to understand what it implies.

I have seen great blogs on the topic such as: https://devblogs.microsoft.com/dotnet/configureawait-faq/

IMHO the docs should provide meaningful context about this commonly but IMHO poorly understood function.

At least a link to great blogs would be great :)