[NeuralChat] Fix RAG example for retrieval plugin parameter change (#…

…1111)

Fix RAG example for retrieval plugin parameter change

Signed-off-by: lvliang-intel <liang1.lv@intel.com>

intel_extension_for_transformers/neural_chat/examples/deployment/rag/askdoc.yaml

@@ -30,7 +30,7 @@ retrieval:
     enable: true
     args:
         input_path: "./askdoc_docs"
-        persist_dir: "./askdoc_persist"
+        persist_directory: "./askdoc_persist"
         response_template: "We cannot find suitable content to answer your query, please contact AskGM to find help. Mail: ask.gm.zizhu@intel.com."
         append: False