Add SamplingParams to model response example

Updated example to include SamplingParams in response call.

Author: Ki-Seki

docs/features/models/vllm_offline.md

@@ -44,15 +44,15 @@ For instance:
 
 ```python
 import outlines
-from vllm import LLM
+from vllm import LLM, SamplingParams
 
 # Create the model
 model = outlines.from_vllm_offline(
     LLM("microsoft/Phi-3-mini-4k-instruct")
 )
 
 # Call it to generate text
-response = model("What's the capital of Latvia?", max_tokens=20)
+response = model("What's the capital of Latvia?", sampling_params=SamplingParams(max_tokens=20))
 print(response) # 'Riga'
 ```