Fix the issue where the last character was not output on UNO R4 WiFi.

Printf.cpp

@@ -15,7 +15,7 @@ int printf(const char* fmt, ...) {
 	va_end(arg_ptr);
 
 	// output to the serial console through the 'Serial'
-	len = Serial.write((uint8_t*)buf, (size_t)len);
+	len = Serial.print(buf);
 
 	return len;
 }

README.md

@@ -14,8 +14,8 @@ This library allows you to output a format string to the serial monitor through
 
 void setup() {
   // put your setup code here, to run once:
-  Serial.begin(9600);
-  while (!Serial);
+  Serial.begin(250000);
+  delay(1000); // `while (!Serial);` is not enough for UNO R4 WiFi
 
   for (float f = 0.0; f <= 1.0 + EPSILON; f += 0.01) {
     printf("f = %4.2f\n", f);