Differentiated API key names to avoid confusion. (#3107)

### What problem does this PR solve?


### Type of change


- [x] Documentation Update

docs/guides/llm_api_key_setup.md

 slug: /llm_api_key_setup
 ---
 
-# Configure your API key
+# Configure model API key
 
-An API key is required for RAGFlow to interact with an online AI model. This guide provides information about setting your API key in RAGFlow.
+An API key is required for RAGFlow to interact with an online AI model. This guide provides information about setting your model API key in RAGFlow.
 
-## Get your API key
+## Get model API key
 
-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.
+For now, RAGFlow supports the following online LLMs. Click the corresponding link to apply for your model 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](https://ai.azure.com/)
 If you find your online LLM is not on the list, don't feel disheartened. The list is expanding, and you can [file a feature request](https://github.com/infiniflow/ragflow/issues/new?assignees=&labels=feature+request&projects=&template=feature_request.yml&title=%5BFeature+Request%5D%3A+) with us! Alternatively, if you have customized or locally-deployed models, you can [bind them to RAGFlow using Ollama, Xinferenc, or LocalAI](./deploy_local_llm.mdx).
 :::
 
-## Configure your API key
+## Configure model API key
 
-You have two options for configuring your API key:
+You have two options for configuring your model API key:
 
 - Configure it in **service_conf.yaml** before starting RAGFlow.
 - Configure it on the **Model Providers** page after logging into RAGFlow.
 
-### Configure API key before starting up RAGFlow
+### Configure model API key before starting up RAGFlow
 
 1. Navigate to **./docker/ragflow**.
 2. Find entry **user_default_llm**:
    
    *After logging into RAGFlow, you will find your chosen model appears under **Added models** on the **Model Providers** page.*
 
-### Configure API key after logging into RAGFlow
+### Configure model API key after logging into RAGFlow
 
 :::caution WARNING
-After logging into RAGFlow, configuring API key through the **service_conf.yaml** file will no longer take effect.
+After logging into RAGFlow, configuring your model API key through the **service_conf.yaml** file will no longer take effect.
 :::
 
 After logging into RAGFlow, you can *only* configure API Key on the **Model Providers** page:
 1. Click on your logo on the top right of the page **>** **Model Providers**.
 2. Find your model card under **Models to be added** and click **Add the model**:
    ![add model](https://github.com/infiniflow/ragflow/assets/93570324/07e43f63-367c-4c9c-8ed3-8a3a24703f4e)
-3. Paste your API key.
+3. Paste your model API key.
 4. Fill in your base URL if you use a proxy to connect to the remote service.
 5. Click **OK** to confirm your changes.
 
 :::note
-If you wish to update an existing API key at a later point:
+To update an existing model API key at a later point:
 ![update api key](https://github.com/infiniflow/ragflow/assets/93570324/0bfba679-33f7-4f6b-9ed6-f0e6e4b228ad)
 :::