CloudFormation is not a language, it is a collection of cloud infrastructure

This tweet is likely referring to the fact that you can place special constructs in the YAML/JSON files to add control flow, thereby making it a crude templating language.

Microsoft has Project Verona

Microsoft has C#, F# and Visual Basic that are rather more significant than Project Verona.

True but I was thinking more in the systems programming context

Ah, I don't think Go, Swift or Hack (from the tweet you are replying to) really apply to systems programming contexts any more than C# does.

Yeah, like those Gos, Javas, Kotlins, C Sharps and so on. A lot of fanciness rolling across companies.