docs: Fix import

docs/my-website/docs/providers/vllm.md

@@ -11,7 +11,7 @@ pip install litellm vllm
 ```python
 import litellm 
 
-response = completion(
+response = litellm.completion(
             model="vllm/facebook/opt-125m", # add a vllm prefix so litellm knows the custom_llm_provider==vllm
             messages=messages,
             temperature=0.2,
@@ -29,7 +29,7 @@ In order to use litellm to call a hosted vllm server add the following to your c
 ```python
 import litellm 
 
-response = completion(
+response = litellm.completion(
             model="openai/facebook/opt-125m", # pass the vllm model name
             messages=messages,
             api_base="https://hosted-vllm-api.co",