message: fix stub for DuckDBPyConnection::df
diff: @@ -46,7 +46,7 @@ class DuckDBPyConnection:
  def close(self) -> None: ...
  def commit(self) -> DuckDBPyConnection: ...
  def cursor(self) -> DuckDBPyConnection: ...
  - def df(self, df: pandas.DataFrame) -> DuckDBPyRelation: ...
  + def df(self) -> Any: ...
  def duplicate(self) -> DuckDBPyConnection: ...
  def execute(self, query: str, parameters: object = ..., multiple_parameter_sets: bool = ...) -> DuckDBPyConnection: ...
  def executemany(self, query: str, parameters: object = ...) -> DuckDBPyConnection: ...
  