Change include guards in quantum/ to pragma once (#11239)

quantum/process_keycode/process_clicky.h

@@ -1,5 +1,4 @@
-#ifndef PROCESS_CLICKY_H
-#define PROCESS_CLICKY_H
+#pragma once
 
 void clicky_play(void);
 bool process_clicky(uint16_t keycode, keyrecord_t *record);
@@ -13,5 +12,3 @@ void clicky_on(void);
 void clicky_off(void);
 
 bool is_clicky_on(void);
-
-#endif