Apply #pragma once, misc cleanup (#12322)

* Apply #pragma once in headers
* Adjust some thermistors formatting
* Misc cleanup and formatting

Marlin/src/HAL/HAL_TEENSY35_36/watchdog_Teensy.h

@@ -19,13 +19,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-
-#ifndef WATCHDOG_TEENSY_H
-#define WATCHDOG_TEENSY_H
-
-#include "HAL.h"
-
-// Arduino Due core now has watchdog support
+#pragma once
 
 void watchdog_init();
 
@@ -34,5 +28,3 @@ inline void watchdog_reset() {
   WDOG_REFRESH = 0xA602;
   WDOG_REFRESH = 0xB480;
 }
-
-#endif // WATCHDOG_TEENSY_H