Not the same level of sophistication, but ast-grep allows this for far more languages, since it is based on the tree-sitter parser library. I have used it with some success on C++. Of course it only works on the AST level, and C++ famously need types for correct parsing, so it sometimes fall short (also on macros).
That is JetBrains Mono. HN is using Verdana, I believe, that one is recommended as the most usable common font.
Smalltalk is ancient. I would say, Unison is an interesting recent experiment, and there are others. But, I am interested in universal revision control, any language.
https://ast-grep.github.io/