Change keyboard level include guards to pragma once (#14248)

* Change keyboard level include guards to `pragma once`

And clean up a lot of layout macros

* Oops

* Remove dangling endif

keyboards/lfkeyboards/issi.h

@@ -1,6 +1,6 @@
+#pragma once
+
 #ifdef ISSI_ENABLE
-#ifndef ISSI_H
-#define ISSI_H
 
 typedef struct ISSIDeviceStruct{
     uint8_t fn_dirty;       // function registers need to be resent
@@ -37,4 +37,3 @@ void activateLED(uint8_t matrix, uint8_t cx, uint8_t cy, uint8_t pwm);
 void update_issi(uint8_t device_addr, uint8_t blocking);
 
 #endif
-#endif