Voxtral stop token (#94)

Author: kirklandsign

llm/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/PromptFormat.java

@@ -67,6 +67,8 @@ public static String getStopToken(ModelType modelType) {
         return "</s>";
       case QWEN_3:
         return "<|endoftext|>";
+      case VOXTRAL:
+        return "</s>";
       default:
         return "";
     }