ansible/changelogs/fragments/79657-warn-for-unsupported-role-arg-spec-fields.yml

bugfixes:
- >
  roles - give a warning for unsupported fields in the role argument spec during implicit ``validate_argument_spec`` tasks.
  The valid portion of the argument spec is used to validate variables to prevent unhandled errors during validation.
  (https://github.com/ansible/ansible/issues/79624, https://github.com/ansible/ansible/issues/84103)  
- validate_argument_spec - give an error for unsupported fields in the argument spec to prevent unhandled errors during validation.