* [OCaml] Fix inconsistent oneOf primitive sample name
* [OCaml] Fix encoding/decoding for free-form required fields
* [OCaml] Change field comment to Odoc, move it after the field
As per Odoc documentation, record field documentation should be *after* the
field, not before.
See https://ocaml.github.io/odoc/odoc/odoc_for_authors.html#special_comments
type `my_record`
* [OCaml] Cleanup non-generated files for ocaml sample
