Fix kill => disable_all_heaters => print_job_timer.stop (#12146)

- Remove `print_job_timer.stop()` from `disable_all_heaters`
- Call `print_job_timer.stop()` for relevant `disable_all_heaters()`.
- Split up `kill()` for watchdog interrupt safety

Marlin/src/sd/cardreader.cpp

@@ -394,7 +394,7 @@ void CardReader::openFile(char * const path, const bool read, const bool subcall
         SERIAL_ERROR_START();
         SERIAL_ERRORPGM("trying to call sub-gcode files with too many levels. MAX level is:");
         SERIAL_ERRORLN((int)SD_PROCEDURE_DEPTH);
-        kill(PSTR(MSG_KILLED));
+        kill();
         return;
       }
 

Marlin/src/sd/usb_flashdrive/Sd2Card_FlashDrive.cpp

@@ -38,7 +38,7 @@ Sd2Card::state_t Sd2Card::state;
 
 // The USB library needs to be called periodically to detect USB thumbdrive
 // insertion and removals. Call this idle() function periodically to allow
-// the USB libary to monitor for such events. This function also takes care
+// the USB library to monitor for such events. This function also takes care
 // of initializing the USB library for the first time.
 
 void Sd2Card::idle() {