[BUG] spaces missing from type hints in generated ocaml code

Created by: bobpoekert

Description

Running the ocaml code generator generates code that fails to build because spaces have been removed from type declarations that should have space. Eg: string option becomes stringoption

openapi-generator version

Both git master and 4.3.1 release

OpenAPI declaration file content or url

https://github.com/stripe/openapi/blob/master/openapi/spec3.yaml, though I'm sure a simpler spec would also fail