I've seen this style of commit on and off for a while now. I'm not a huge fan, but I get the idea. What I hadn't realised is that there was a "standard" behind this and even some documentation for it.
A proposed standard for "docstrings" for TypeScript. Well, not docstrings in the Lisp/Python sense, but comments that can be used to document an API in place and allow for the generation of documentation from them.
The Inner Workings of Python Dataclasses Explained
Everything you ever wanted to know about Python's dataclasses. And probably more. And probably stuff you didn't care to know. And probably stuff you didn't know you'd ever want to know, or not.