Heap-Buffer-Overread in contains_whitespace when calling parser_validate after supplying a maliciously crafted buffer to parser_parse

A fuzz crash case was discovered, resulting in a `heap-buffer-overread` in the `contains_whitespace` function. This crash was not exploitable in the primary use case of the library, however a length check was added to prevent this case from triggering. This report was awarded a one-time bounty as it was the first valid submission for this target. Future crashes will need to be exploitable to be eligible for bounties for this component going forward.