document compiled_modules

[bjarthur]

i first learned about this purportedly great (haven't tried it myself yet) feature on discourse. is there a reason it's not documented here, or even in interpreter.jl?

[KristofferC]

https://juliadebug.github.io/JuliaInterpreter.jl/stable/dev_reference/#JuliaInterpreter.compiled_methods and
https://juliadebug.github.io/JuliaInterpreter.jl/stable/dev_reference/#JuliaInterpreter.compiled_modules

But we could give a reference to that here as well.