Add Pp_ast ppxlib to this repo

[pedrobslisboa]

Description

The major issue with maintaining this repo is that the AST tree can change over time. For example, nowadays, the astexplorer with ocaml and reason is outdated.

As ppxlib provided a builtin way to print the ast tree we can now keep the astexplorer always updated with the new tree

Warning

For now I'm pinning ppxlib as we still not have the pp_ast on a version and the json feature is under review: ocaml-ppx/ppxlib#526

Testing on astexplorer

• Clone the astexplorer repo: https://github.com/pedrobslisboa/astexplorer/
• Checkout to this branch: feat/update-refmt
• In website folder of astexplorer, call yarn link <path-to-astexplorer-refmt>.

Screenshots

Before:

After:

[pedrobslisboa]

Btw, I need to update the README

[jchavarri]

Thanks so much! I think the readme should be updated to reflect these changes. Edit: oh, i just saw your comment 😅

[pedrobslisboa]

@jchavarri README updated