Fix a bug in `Key.isLayerShift()`

It was failing to exclude `MoveToLayer()` keys, so it would return `true`
incorrectly for them.

Signed-off-by: Michael Richters <gedankenexperimenter@gmail.com>

src/kaleidoscope/key_defs.h

@@ -223,7 +223,8 @@ class Key {
   // worth singling them out.
   constexpr bool isLayerShift() const {
     return (isLayerKey() &&
-            (keyCode_ >= LAYER_SHIFT_OFFSET));
+            keyCode_ >= LAYER_SHIFT_OFFSET &&
+            keyCode_ < LAYER_MOVE_OFFSET);
   }
 
  private: