Update demo/llm_contory.c

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

demo/llm_contory.c

@@ -59,7 +59,7 @@ static void send(int argc, char *argv[])
     if (llm_handle == RT_NULL)
     {
         rt_kprintf("llm_handle is null\n");
-        return；
+        return;
     }
 
     rt_snprintf(prompt, sizeof(prompt), LED_PROMPT, argv[1]);