Doc for agent about train_cn and train_agentfabric_llm_tool_use_cn

[slin000111]

Change Summary

1. add docs/training_llms/train_cn.md
2. add docs/training_llms/train_agentfabric_llm_tool_use_cn.md
3. fix finetune script in train documentation, docs/training_llms/train.md
4. Update swift version in the example of finetune_llm

Related issue number

fix #420

Checklist

• [ ] The pull request title is a good summary of the changes - it will be used in the changelog
• [ ] Unit tests for the changes exist
• [x] Run pre-commit install and pre-commit run --all-files before git commit, and passed lint check.
• [ ] Some cases need DASHSCOPE_TOKEN_API to pass the Unit Tests, I have at least pass the Unit tests on local
• [ ] Documentation reflects the changes where applicable
• [ ] My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers