Clarify SNI host header stuff

Author: lfrancke

docs/modules/nifi/pages/troubleshooting/index.adoc

@@ -87,7 +87,7 @@ nodes:
 These properties control NiFi's SNI validation behavior:
 
 * `nifi.web.https.sni.required`: When `true`, NiFi requires that HTTPS requests include the SNI extension (containing the `server_name`). Setting to `false` allows connections without SNI. Be aware: SNI is _not_ used for IP based connections, so if this is set to `true` any connections using IPs only will not work.
-* `nifi.web.https.sni.host.check`: When `true`, NiFi validates that the SNI `server_name` is a valid Subject in the Certificate. Setting to `false` disables this hostname matching check.
+* `nifi.web.https.sni.host.check`: When `true`, NiFi validates that the value of the `Host` header is a valid Subject in the Certificate. Setting to `false` disables this hostname matching check.
 
 WARNING: Disabling SNI validation reduces security by allowing connections with mismatched hostnames. Only use this workaround when proper certificate configuration is not feasible.