Apply #pragma once, misc cleanup (#12322)

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

Marlin/src/feature/caselight.h

@@ -19,9 +19,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-
-#ifndef __CASELIGHT_H__
-#define __CASELIGHT_H__
+#pragma once
 
 extern uint8_t case_light_brightness;
 extern bool case_light_on;
@@ -29,5 +27,3 @@ extern uint8_t case_light_brightness_sav;   // saves brighness info when case_li
 extern bool case_light_arg_flag;  // flag to notify if S or P argument type
 
 void update_case_light();
-
-#endif // __CASELIGHT_H__