• replaces usage of the removed req.routerPath with the updated req.routeOptions.url in inject.test.js
• updates the note in the documentation to reflect the change from request.routerPath, routerMethod, and context.config to request.routeOptions.url, routeOptions.method, and routeOptions.config within the custom "not found" handler.

Checklist

• run npm run test and npm run benchmark
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct