Fix some serial char, echo

Co-Authored-By: X-Ryl669 <3277165+X-Ryl669@users.noreply.github.com>

Marlin/src/sd/cardreader.cpp

@@ -369,7 +369,7 @@ void CardReader::printFilename() {
     #if ENABLED(LONG_FILENAME_HOST_SUPPORT)
       selectFileByName(dosFilename);
       if (longFilename[0]) {
-        SERIAL_ECHO(' ');
+        SERIAL_CHAR(' ');
         SERIAL_ECHO(longFilename);
       }
     #endif