🩹 Fix some serial chars

Author: thinkyhead

Marlin/src/core/mstring.h

@@ -98,7 +98,7 @@ class MString {
 
   void debug(FSTR_P const f) {
     #if ENABLED(MSTRING_DEBUG)
-      SERIAL_ECHOLN(f, ':', uintptr_t(str), ' ', length(), ' ', str);
+      SERIAL_ECHOLN(f, AS_CHAR(':'), uintptr_t(str), AS_CHAR(' '), length(), AS_CHAR(' '), str);
     #endif
   }
 

Marlin/src/feature/runout.h

@@ -159,7 +159,7 @@ class TFilamentMonitor : public FilamentMonitorBase {
         if (ran_out) {
           #if ENABLED(FILAMENT_RUNOUT_SENSOR_DEBUG)
             SERIAL_ECHOPGM("Runout Sensors: ");
-            for (uint8_t i = 0; i < 8; ++i) SERIAL_ECHO('0' + char(runout_flags[i]));
+            for (uint8_t i = 0; i < 8; ++i) SERIAL_CHAR('0' + char(runout_flags[i]));
             SERIAL_ECHOLNPGM(" -> ", extruder, " RUN OUT");
           #endif
 

Marlin/src/module/temperature.cpp

@@ -1487,7 +1487,7 @@ void Temperature::_temp_error(
       OPTCODE(HAS_TEMP_CHAMBER, case H_CHAMBER: SERIAL_ECHOPGM(STR_HEATER_CHAMBER); break)
       OPTCODE(HAS_TEMP_BED,     case H_BED:     SERIAL_ECHOPGM(STR_HEATER_BED);     break)
       default:
-        if (real_heater_id >= 0) SERIAL_ECHO('E', real_heater_id);
+        if (real_heater_id >= 0) SERIAL_ECHO(AS_CHAR('E'), real_heater_id);
     }
     #if ENABLED(ERR_INCLUDE_TEMP)
       SERIAL_ECHOLNPGM(STR_DETECTED_TEMP_B, deg, STR_DETECTED_TEMP_E);