examples/Keyboardio/Atreus: Use `MoveToLayer`

On the `Upper` layer, we used to have a macro that moved us back to the QWERTY
layer. It was made before we had `MoveToLayer` available. Now that we do have
it, lets use that instead of the macro.

We still keep the macro around, for the sake of compatibility, so that if anyone
who has the old macro in EEPROM, but updates the firmware, will have the key
working still.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

examples/Devices/Keyboardio/Atreus/Atreus.ino

@@ -82,15 +82,15 @@ KEYMAPS(
 
   [UPPER] = KEYMAP_STACKED
   (
-       Key_Insert      ,Key_Home                 ,Key_UpArrow   ,Key_End        ,Key_PageUp
-      ,Key_Delete      ,Key_LeftArrow            ,Key_DownArrow ,Key_RightArrow ,Key_PageDown
-      ,XXX             ,Consumer_VolumeIncrement ,XXX           ,XXX            ,___ ,___
-      ,M(MACRO_QWERTY) ,Consumer_VolumeDecrement ,___           ,___            ,___ ,___
-
-                ,Key_UpArrow   ,Key_F7          ,Key_F8          ,Key_F9         ,Key_F10
-                ,Key_DownArrow ,Key_F4          ,Key_F5          ,Key_F6         ,Key_F11
-      ,___      ,XXX           ,Key_F1          ,Key_F2          ,Key_F3         ,Key_F12
-      ,___      ,___           ,M(MACRO_QWERTY) ,Key_PrintScreen ,Key_ScrollLock ,Consumer_PlaySlashPause
+       Key_Insert          ,Key_Home                 ,Key_UpArrow   ,Key_End        ,Key_PageUp
+      ,Key_Delete          ,Key_LeftArrow            ,Key_DownArrow ,Key_RightArrow ,Key_PageDown
+      ,XXX                 ,Consumer_VolumeIncrement ,XXX           ,XXX            ,___ ,___
+      ,MoveToLayer(QWERTY) ,Consumer_VolumeDecrement ,___           ,___            ,___ ,___
+
+                ,Key_UpArrow   ,Key_F7              ,Key_F8          ,Key_F9         ,Key_F10
+                ,Key_DownArrow ,Key_F4              ,Key_F5          ,Key_F6         ,Key_F11
+      ,___      ,XXX           ,Key_F1              ,Key_F2          ,Key_F3         ,Key_F12
+      ,___      ,___           ,MoveToLayer(QWERTY) ,Key_PrintScreen ,Key_ScrollLock ,Consumer_PlaySlashPause
    )
 )
 /* *INDENT-ON* */
@@ -111,6 +111,10 @@ KALEIDOSCOPE_INIT_PLUGINS(
 const macro_t *macroAction(uint8_t macroIndex, uint8_t keyState) {
   switch (macroIndex) {
   case MACRO_QWERTY:
+    // This macro is currently unused, but is kept around for compatibility
+    // reasons. We used to use it in place of `MoveToLayer(QWERTY)`, but no
+    // longer do. We keep it so that if someone still has the old layout with
+    // the macro in EEPROM, it will keep working after a firmware update.
     Layer.move(QWERTY);
     break;
   default: