Review impact of static local functions on existing rules

[sharwell]

https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8#static-local-functions

[sharwell]

I don't think any rules need to be updated to account for this. However, we have some sections of code that scan methods for all variable names (to avoid conflicts), and this code will need to be updated to account for the scoping changes brought in by C# 8.