point out the sslcert web page for -k/--insecure

docs/curl.1

@@ -546,6 +546,9 @@ and transfers. All SSL connections are attempted to be made secure by using
 the CA certificate bundle installed by default. This makes all connections
 considered "insecure" to fail unless \fI-k/--insecure\fP is used.
 
+See this online resource for further details:
+\fBhttp://curl.haxx.se/docs/sslcerts.html\fP
+
 If this option is used twice, the second time will again disable it.
 .IP "--key <key>"
 (SSL) Private key file name. Allows you to provide your private key in this