Added: LDM notes for June 15, 2020

[SingleAccretion]

C# Language Design Notes for June 15, 2020

Records:
1. modreq for init accessors
2. Initializing readonly fields in same type
3. init methods
4. Equality dispatch
5. Confirming some previous design decisions
6. IEnumerable.Current

[HaloFour]

I'm curious if there will be an effort to also standardize how the compilers handle a property accessor with a modreq modifier? It's quite concerning that C#, VB.NET and F# all handle the modreq(IsExternalInit) differently. Is the behavior here not a part of the CLR spec?

I'll make the wild assumption that F# will be updated in time to properly respect the modreq, but will anything prevent an older version of F# from targeting the newer runtime?