swap: use correct direction for it_wrap

Always using .forward results in a crash when running `swap previous` on
the first view in stack which should be wrapped.

river/command/swap.zig

@@ -51,7 +51,7 @@ pub fn swap(
     );
     var it_wrap = ViewStack(View).iter(
         if (direction == .next) output.views.first else output.views.last,
-        .forward,
+        if (direction == .next) .forward else .reverse,
         output.pending.tags,
         filter,
     );