Parameter $limit of preg_split should be nullable

PHP documentation says:

>`limit`
>If specified, then only substrings up to `limit` are returned with the rest of the string being placed in the last substring. A `limit` of -1 or 0 means "no limit" and, as is standard across PHP, **you can use `NULL` to skip to the `flags` parameter**.

So `$limit` should be `?int` but in the generated `preg_split` function it is `int` only.