Possibility of replacing code mirror with Monaco editor

[Rafi993]

It would be awesome if we could explore the possibility of using Monaco editor instead of code mirror since it comes with intellisense and some of the default editor features ( commenting, auto-complete, code-folding )

[CrossEye]

If you want to create a PR for this, I'm all ears.

It seems that the public REPL is simply being served from the docs repo, so for the moment, I'm guessing any work we do should be there. I don't know if there are users of this repo at all now. At some point I'll try to find out.