Trace with names instead of lambda

[Machine-Jonte]

Hi!

First, thanks super much for this awesome open-source implementation of Scheme!

I do wonder about the stack trace. With functions defined outside of the implementation, the names of the functions are not known. Is there a way that you know how to extend this repo to support Scheme defined function names? e.g. I would like an error message to go from:

> (define (f a b) (+ a b))
> (f 3 "hej")
error: invalid argument for +: expected number, but got hej
trace: 
        (+)
        (λ (a b))
        (λ)

to

> (define (f a b) (+ a b))
> (f 3 "hej")
error: invalid argument for +: expected number, but got hej
trace: 
        (+)
        (f (a b))
        (...? <-- Unsure about this guy)