Update env sample file

env.example

@@ -74,7 +74,8 @@ TIMEOUT=240
 TEMPERATURE=0
 ### Max concurrency requests of LLM
 MAX_ASYNC=4
-### Max tokens send to LLM for entity relation summaries (less than context size of the model)
+### MAX_TOKENS: max tokens send to LLM for entity relation summaries (less than context size of the model)
+### MAX_TOKENS: set as num_ctx option for Ollama by API Server
 MAX_TOKENS=32768
 ### LLM Binding type: openai, ollama, lollms
 LLM_BINDING=openai