I would imagine that a "real programming language" here means not only any Turing-complete language but also a language that has been consistently at the top 10 most popular programming languages in the world for a while (which javascript is, and typescript is its superset).
I would hope that we can do better than that. Both Nix and Dhall are designed for readability in the limited niche of configuration management, and their authors considered that design choice to be important enough on its own to merit a new language. Dhall is explicitly not Turing-complete.
