SimpleChat:ChatRequestOptions: max_tokens

As some times based on the query from the user, the ai model may get
into a run away kind of generation with repeatations etal, so adding
max_tokens to try and limit this run away behaviour, if possible.

examples/server/public_simplechat/simplechat.js

@@ -34,7 +34,8 @@ let gUsageMsg = `
 
 // Add needed fields wrt json object to be sent wrt LLM web services completions endpoint.
 let gChatRequestOptions = {
-    "temperature": 0.7
+    "temperature": 0.7,
+    "max_tokens": 2048
 };
 
 class SimpleChat {