Remove stale TODO from Client.send_roots_list_changed

The lowlevel Server has handled roots/list_changed via on_roots_list_changed
for a while (see tests/interaction/lowlevel/test_roots.py); the comment was
left behind when the pragma next to it was removed.

Author: maxisbey

src/mcp/client/client.py

@@ -946,5 +946,4 @@ async def list_tools(
     @deprecated("The roots capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
     async def send_roots_list_changed(self) -> None:
         """Send a notification that the roots list has changed."""
-        # TODO(Marcelo): Currently, there is no way for the server to handle this. We should add support.
         await self.session.send_roots_list_changed()  # pyright: ignore[reportDeprecated]