docs: add CURLOPT_NOPROGRESS to CURLOPT_XFERINFOFUNCTION example by To1ne · Pull Request #13348 · curl/curl

It's important to set CURLOPT_NOPROGRESS to 0 if you want your transfer callback function, set by CURLOPT_XFERINFOFUNCTION, getting called. To emphasize this to the users, add this to the code exam...