Make aroundNext only affect the next button

Before this change, aroundNext was able to change more buttons than just
the very next one, provided the next button was released after some
other buttons were pressed.  For example, suppose we had

    (defalias
      nsh (around-next sft))

Then the old behaviour would give

    T@nsh Ta Tb       ==> Ab
    T@nsh Pa Pb Ra Rb ==> AB

while the intended behaviour (and the one that this commit introduces)
would be

    T@nsh Ta Tb       ==> Ab
    T@nsh Pa Pb Ra Rb ==> Ab

src/KMonad/Button.hs

@@ -177,9 +177,10 @@ around outer inner = Button
 aroundNext ::
      Button -- ^ The outer 'Button'
   -> Button -- ^ The resulting 'Button'
-aroundNext b = onPress $ await isPress $ \e -> do
+aroundNext b = onPress $ await isPress $ \_ -> do
   runAction $ b^.pressAction
-  await (isReleaseOf $ e^.keycode) $ \_ -> do
+  -- Wait for the next *event*, regardless of what it is
+  await (pure True) $ \_ -> do
     runAction $ b^.releaseAction
     pure NoCatch
   pure NoCatch
@@ -351,5 +352,3 @@ layerNext :: LayerTag -> Button
 layerNext t = onPress $ do
   layerOp (PushLayer t)
   await isPress (\_ -> whenDone (layerOp $ PopLayer t) *> pure NoCatch)
-
-