Update demonotes.md

demonotes.md

@@ -114,6 +114,7 @@ newServer({address="9.9.9.9", name="quad9", order=2 })
 systemctl stop pdns-recursor
 dig switch.ch @localhost
 ```
+/!\ --> remember to restart pdns-recursor afterwards, our the rest of this demo will fail miserably. <-- /!\
 
 
 dnsdist demo: block firefox auto-doh