Merge pull request #5892 from thinkyhead/rc_msg_heating_pstr

Use PSTR for MSG_HEATING

Marlin/Marlin_main.cpp

       }
     #endif
 
-    if (code_value_temp_abs() > thermalManager.degHotend(target_extruder)) status_printf(0, "E%i %s", target_extruder + 1, MSG_HEATING);
+    if (code_value_temp_abs() > thermalManager.degHotend(target_extruder)) status_printf(0, "E%i %s", target_extruder + 1, PSTR(MSG_HEATING));
   }
 
   #if ENABLED(AUTOTEMP)
       else print_job_timer.start();
     #endif
 
-    if (thermalManager.isHeatingHotend(target_extruder)) status_printf(0, "E%i %s", target_extruder + 1, MSG_HEATING);
+    if (thermalManager.isHeatingHotend(target_extruder)) status_printf(0, "E%i %s", target_extruder + 1, PSTR(MSG_HEATING));
   }
 
   #if ENABLED(AUTOTEMP)

Marlin/ultralcd.cpp

   lcd_status_message_level = level;
   va_list args;
   va_start(args, status);
-  vsnprintf(lcd_status_message, 3 * (LCD_WIDTH), status, args);
+  vsnprintf_P(lcd_status_message, 3 * (LCD_WIDTH), status, args);
   va_end(args);
   lcd_finishstatus(level > 0);
 }