Fix serial.h indents

Marlin/src/core/serial.h

@@ -73,11 +73,11 @@ extern uint8_t marlin_debug_flags;
 
 #define SERIAL_CHAR(x)          SERIAL_OUT(write, x)
 #define SERIAL_ECHO(x)          SERIAL_OUT(print, x)
-#define SERIAL_ECHO_F(V...)      SERIAL_OUT(print, V)
+#define SERIAL_ECHO_F(V...)     SERIAL_OUT(print, V)
 #define SERIAL_ECHOLN(x)        SERIAL_OUT(println, x)
 #define SERIAL_PRINT(x,b)       SERIAL_OUT(print, x, b)
 #define SERIAL_PRINTLN(x,b)     SERIAL_OUT(println, x, b)
-#define SERIAL_PRINTF(V...)      SERIAL_OUT(printf, V)
+#define SERIAL_PRINTF(V...)     SERIAL_OUT(printf, V)
 #define SERIAL_FLUSH()          SERIAL_OUT(flush)
 
 #if TX_BUFFER_SIZE > 0