add a .clang-format file (#9154)

src/input/kbMatrixImpl.h

@@ -9,11 +9,10 @@
  *      to your device as you wish, but you always need to have separate event
  *      handlers, thus you need to have a RotaryEncoderInterrupt implementation.
  */
-class KbMatrixImpl : public KbMatrixBase
-{
-  public:
-    KbMatrixImpl();
-    void init();
+class KbMatrixImpl : public KbMatrixBase {
+public:
+  KbMatrixImpl();
+  void init();
 };
 
 extern KbMatrixImpl *kbMatrixImpl;