* main: (22 commits)
  playground: fix warning errors
  playground: add test for bad error msg
  playground: use js_of_ocaml library (#654)
  chore: update nix flakes (#652)
  playground: bring back cmijs hack (#648)
  Update CONTRIBUTING.md to include an installation step for melange.opam and a link to the Pull Request instructions (#651)
  playground: specify ppx dep (#646)
  playground: package + es6 + direct reason compilation (#632)
  feat: add `-rectypes` (#644)
  fix changelog
  fix: spurious warning 61 in externals
  test: show spurious warning 61 in externals
  test: show how to disable ppx alerts (#642)
  fix: disable warning 61 (`unboxable-type-in-prim-decl`) for deriving abstract externals
  test: show spurious warning on single field records with [@@deriving abstract]
  chore: format runtime / belt / node libraries (#640)
  chore: test on OCaml 5.1 (#639)
  chore: require dune 3.8, format, cleanup (#638)
  refactor: Don't use `(stdlib ...)` for the `Js.*` runtime (#637)
  chore: snapshot JS test files (#636)
  ...