curl_easy_setopt.3: NOPROGRESS also affects the callback

docs/libcurl/curl_easy_setopt.3

@@ -68,8 +68,9 @@ A parameter set to 1 tells the library to include the header in the body
 output. This is only relevant for protocols that actually have headers
 preceding the data (like HTTP).
 .IP CURLOPT_NOPROGRESS
-A parameter set to 1 tells the library to shut off the built-in progress meter
-completely.
+Pass a long. If set to 1, it tells the library to shut off the progress meter
+completely. It will also present the \fICURLOPT_PROGRESSFUNCTION\fP from
+getting called.
 
 Future versions of libcurl are likely to not have any built-in progress meter
 at all.