update wrong prompt placeholder pattern

Author: leehuwuj

helpers/env-variables.ts

@@ -495,7 +495,7 @@ Disable this prompt to disable the next question suggestions feature.`,
       value: `"You're a helpful assistant! Your task is to suggest the next question that user might ask. 
 Here is the conversation history
 ---------------------
-$conversation
+{conversation}
 ---------------------
 Given the conversation history, please give me 3 questions that you might ask next!
 Your answer should be wrapped in three sticks which follows the following format:

templates/components/llamaindex/typescript/streaming/suggestion.ts

@@ -12,7 +12,7 @@ export async function generateNextQuestions(conversation: ChatMessage[]) {
     .map((message) => `${message.role}: ${message.content}`)
     .join("\n");
   const message = NEXT_QUESTION_PROMPT.replace(
-    "$conversation",
+    "{conversation}",
     conversationText,
   );