Fix onRequest hook documentation

[mattiapv]

Added missing async and await keywords, try...catch block. This prevents server crashes caused by missing await on jwtVerify() function.

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

[mcollina]

None of this are needed, why did you add them?

[mattiapv]

None of this are needed, why did you add them?

Because without awaiting jwtVerify() the server crash.

You can try the cookie or the onlyCookie example.

If you make a call to http://localhost:3000/verifyCookie the server crash.

If I add await request.jwtVerify(), I receive the correct error (FST_JWT_NO_AUTHORIZATION_IN_HEADER) and the server doesn't crash.

[mcollina]

lgtm