Add parameter names to functions and type constructors package_interface.json

[just-maiyak]

I am exploring the package_interface.json spec in an effort, with @GearsDatapacks, to build a CLI tool to peek at package docs (somewhat related to #2288).
I think the only thing missing to print out full function signatures would be the symbols for function parameters. I see labels and ids are already present in the spec, but I figure that the signature would be hard to read if there are no labels. I also see that the function generating the package_interface.json is already passed the AST, so i figure it is possible to add the information in the file.
Could parameter names be added in the spec of package_interface.json ?

[lpil]

Parameter names are internal and not part of the public interface of a function.

[just-maiyak]

Okay, we'll just print the types then. Thanks 🙂