enable rustbot note in triagebot.toml

triagebot.toml

@@ -3,6 +3,8 @@ allow-unauthenticated = ["bug", "invalid", "question", "enhancement"]
 
 [assign]
 
+[note]
+
 [ping.wg-meta]
 message = """\
 This is just testing some functionality, please ignore this ping.