Doc pages breaking with Zod's bigint type

[juliangehring]

Using the bigint type of Zod seems to be breaking the /docs and redocs pages. A simple example based on the user guide, modified to use Zod's bigint instead of the normal Int:

import { OpenAPIRouter, OpenAPIRoute, Path, Int } from '@cloudflare/itty-router-openapi';
import { z } from 'zod'

export class ToDoFetch extends OpenAPIRoute {
	static schema = {
		parameters: {
			todoId: Path(z.coerce.bigint().nonnegative(), { // <-- using `bigint` here
				description: 'ToDo ID',
			}),
		},
	}

	async handle(
		request: Request,
		env: any,
		context: any,
		data: any
	) {
		const { todoId } = data.params
		return new Response(todoId);
	}
}

const router = OpenAPIRouter()
router.get('/todos/:todoId', ToDoFetch)

export default {
	fetch: router.handle,
}

The docs page then throws: "Failed to load API definition. Fetch error response status is 500 /openapi.json"
The redocs page is stuck in "Loading..."

When using the standard Int type instead, the doc pages load normally.