Fixed comment with correct FQDN (#4152)

libraries/ESPmDNS/examples/mDNS_Web_Server/mDNS_Web_Server.ino

@@ -47,7 +47,7 @@ void setup(void)
 
     // Set up mDNS responder:
     // - first argument is the domain name, in this example
-    //   the fully-qualified domain name is "esp8266.local"
+    //   the fully-qualified domain name is "esp32.local"
     // - second argument is the IP address to advertise
     //   we send our IP address on the WiFi network
     if (!MDNS.begin("esp32")) {