Added supported LLMs (#1517)

### What problem does this PR solve?

_Briefly describe what this PR aims to solve. Include background context
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### Type of change

- [x] Documentation Update

docs/guides/llm_api_key_setup.md

@@ -12,8 +12,14 @@ An API key is required for RAGFlow to interact with an online AI model. This gui
 For now, RAGFlow supports the following online LLMs. Click the corresponding link to apply for your API key. Most LLM providers grant newly-created accounts trial credit, which will expire in a couple of months, or a promotional amount of free quota.
 
 - [OpenAI](https://platform.openai.com/login?launch),
+- Azure-OpenAI,
+- Gemini,
+- Groq,
+- Mistral,
+- Bedrock,
 - [Tongyi-Qianwen](https://dashscope.console.aliyun.com/model),
 - [ZHIPU-AI](https://open.bigmodel.cn/),
+- MiniMax
 - [Moonshot](https://platform.moonshot.cn/docs),
 - [DeepSeek](https://platform.deepseek.com/api-docs/),
 - [Baichuan](https://www.baichuan-ai.com/home),