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/sixkeyboard/sixkeyboard.h

@@ -1,20 +1,7 @@
-#ifndef SIXKEYBOARD_H
-#define SIXKEYBOARD_H
+#pragma once
 
 #include "quantum.h"
 
-// This macro is an example of using a non-standard row-column matrix. The
-// keyboard in question had 11 rows and 8 columns, but the rows were not all
-// horizontal, and the columns were not all vertical. For example, row 2
-// contained "Print Screen", "N", "M", ",", ".", "/", "Right Shift", and
-// "Left Alt". Column 0 contained "F6", "7", "O", "'", "Q", "D", "B",
-// "Left Alt", "Up Arrow", and "Down Arrow".
-//
-// The macro makes programming the keys easier and in a more straight-forward
-// manner because it realigns the keys into a 6x15 sensible keyboard layout
-// instead of the obtuse 11x8 matrix.
-
-
 /*
  * ┌───┬───┬───┐
  * │ A │ B │ C │
@@ -24,11 +11,8 @@
  */
 #define LAYOUT_ortho_2x3( \
     k00, k01, k02, \
-    k10, k11, k12  \
-  ) { \
+    k10, k11, k12 \
+) { \
     { k00, k01, k02 }, \
-    { k10, k11, k12 }  \
+    { k10, k11, k12 } \
 }
-
-
-#endif