xtuner下的self.md文档有漏写

在2.6 网页demo运行前，需先进入到 /root/personal_assistant/code/InternLM目录下
否则demo在推理时会报错
即将
```
streamlit run /root/personal_assistant/code/InternLM/web_demo.py --server.address 127.0.0.1 --server.port 6006
```
改成
```
cd /root/personal_assistant/code/InternLM
streamlit run /root/personal_assistant/code/InternLM/web_demo.py --server.address 127.0.0.1 --server.port 6006
```

Open the xtuner self.md documentation and find section 2.6, then compare its web demo command with the issue report. Update the instructions to enter /root/personal_assistant/code/InternLM before running streamlit, and verify that the documented command sequence is complete.

Escrito por el modelo de indexación a partir del texto del issue.