Final tweaks to M111 output

Marlin/Marlin_main.cpp

@@ -4379,7 +4379,7 @@ inline void gcode_M111() {
     uint8_t comma = 0;
     for (uint8_t i = 0; i < COUNT(debug_strings); i++) {
       if (TEST(marlin_debug_flags, i)) {
-        if (comma++) SERIAL_CHAR('|');
+        if (comma++) SERIAL_CHAR(',');
         serialprintPGM((char*)pgm_read_word(&(debug_strings[i])));
       }
     }