Rename OpenRouter and LiteLLM LlmApiType

Author: par4m

docs/docs/ai/llm.mdx

@@ -175,7 +175,7 @@ litellm --config config.yml
 
 ```python
 cocoindex.LlmSpec(
-    api_type=cocoindex.LlmApiType.LITELLM,
+    api_type=cocoindex.LlmApiType.LITE_LLM,
     model="deepseek-r1", 
     address="http://127.0.0.1:4000", # default url of LiteLLM
 )
@@ -198,7 +198,7 @@ A spec for OpenRouter looks like this:
 
 ```python
 cocoindex.LlmSpec(
-    api_type=cocoindex.LlmApiType.OPENROUTER,
+    api_type=cocoindex.LlmApiType.OPEN_ROUTER,
     model="deepseek/deepseek-r1:free",
 )
 ```

python/cocoindex/llm.py

@@ -9,8 +9,8 @@ class LlmApiType(Enum):
     OLLAMA = "Ollama"
     GEMINI = "Gemini"
     ANTHROPIC = "Anthropic"
-    LITELLM = "LiteLlm"
-    OPENROUTER = "OpenRouter"
+    LITE_LLM = "LiteLlm"
+    OPEN_ROUTER = "OpenRouter"
 
 
 @dataclass