Add a get cosine scaled reward factory function to trl/rewards and export it from trl.rewards .

Add a get cosine scaled reward factory function to trl/rewards and export it from trl.rewards .: a task in HF ML Tasksmith (Harbor dataset). The function signature is: python def get cosine scaled reward( max len: int, min value wrong: float = -1.0, max value wrong: float = -0.5, min value…

The task

The function signature is: ```python def get_cosine_scaled_reward( max_len: int, min_value_wrong: float = -1.0, max_value_wrong: float = -0.5, min_value_correct: float = 0.5, max_value_correct: float = 1.0, ) -> Callable: ... ```

Part of FineEnvs/HF_ML_Tasksmith.