[Doc] Update user doc index (#1581)

Add user doc index to make the user guide more clear
- vLLM version: v0.9.1
- vLLM main:
49e8c7ea25

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

docs/source/user_guide/feature_guide/lora.md

@@ -0,0 +1,8 @@
+# LoRA Adapters Guide
+
+Like vLLM, vllm-ascend supports LoRA as well. The usage and more details can be found in [vLLM official document](https://docs.vllm.ai/en/latest/features/lora.html).
+
+You can also refer to [this](https://docs.vllm.ai/en/latest/models/supported_models.html#list-of-text-only-language-models) to find which models support LoRA in vLLM.
+
+## Tips
+If you fail to run vllm-ascend with LoRA, you may follow [this instruction](https://vllm-ascend.readthedocs.io/en/latest/user_guide/graph_mode.html#fallback-to-eager-mode) to disable graph mode and try again.