update documents

Author: weikaiwen

docs/source/Instruction/命令行参数.md

@@ -351,6 +351,7 @@ Vera使用`target_modules`, `target_regex`, `modules_to_save`三个参数.
 - check_model: 检查本地模型文件有损坏或修改并给出提示，默认为True。如果是断网环境，请设置为False。
 - 🔥create_checkpoint_symlink: 额外创建checkpoint软链接，方便书写自动化训练脚本。best_model和last_model的软链接路径分别为f'{output_dir}/best'和f'{output_dir}/last'。
 - loss_type: loss类型。默认为None，使用模型自带损失函数。
+- channel_list : 数据集包含的channel列表。默认为None。结合`--loss_type channel_loss`使用，可参考[这里](https://github.com/modelscope/ms-swift/blob/main/examples/train/plugins/channel_loss.sh)。
 - 🔥packing: 是否使用序列packing提升计算效率，默认为False。当前支持`swift pt/sft`。
   - 注意：使用packing请结合`--attn_impl flash_attn`使用且"transformers>=4.44"，具体查看[该PR](https://github.com/huggingface/transformers/pull/31629)。
   - 支持的多模态模型参考：https://github.com/modelscope/ms-swift/blob/main/examples/train/packing/qwen2_5_vl.sh

docs/source_en/Instruction/Command-line-parameters.md

@@ -360,6 +360,7 @@ Training arguments include the [base arguments](#base-arguments), [Seq2SeqTraine
 - check_model: Check local model files for corruption or modification and give a prompt, default is True. If in an offline environment, please set to False.
 - 🔥create_checkpoint_symlink: Creates additional checkpoint symlinks to facilitate writing automated training scripts. The symlink paths for `best_model` and `last_model` are `f'{output_dir}/best'` and `f'{output_dir}/last'` respectively.
 - loss_type: Type of loss. Defaults to None, which uses the model's built-in loss function.
+- channel_list：List of channels included in the dataset. Defaults to None. Used in conjunction with `--loss_type channel_loss`. Refer to [this example](https://github.com/modelscope/ms-swift/blob/main/examples/train/plugins/channel_loss.sh) for more details.
 - 🔥packing: Whether to use sequence packing to improve computational efficiency. The default value is False. Currently supports `swift pt/sft`.
   - Note: When using packing, please combine it with `--attn_impl flash_attn` and ensure "transformers>=4.44". For details, see [this PR](https://github.com/huggingface/transformers/pull/31629).
   - Supported multimodal models reference: https://github.com/modelscope/ms-swift/blob/main/examples/train/packing/qwen2_5_vl.sh

examples/train/plugins/channel_loss.sh

@@ -1,4 +1,5 @@
 # use loss_type channel_loss
+# channel_list specifies the channels included in the dataset
 # data should have 'channel' field
 # eg.
 # {"channel": "chat",
@@ -27,4 +28,5 @@ swift sft \
     --system 'You are a helpful assistant.' \
     --warmup_ratio 0.05 \
     --dataloader_num_workers 4 \
-    --loss_type channel_loss
+    --loss_type channel_loss \
+    --channel_list 'chat' 'math' 'code'