typo

src/system.cpp

@@ -373,7 +373,7 @@ void System::show_mem(const char * note) {
 
 // send periodic MQTT message with system information
 void System::send_heartbeat() {
-    // don't send heartbeat if WiFi or MQTT is connected
+    // don't send heartbeat if WiFi or MQTT is not connected
     if (!Mqtt::connected()) {
         return;
     }