trival (#1760)

### What problem does this PR solve?

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/db/db_models.py

@@ -824,11 +824,12 @@ class Dialog(DataBaseModel):
     do_refer = CharField(
         max_length=1,
         null=False,
-        help_text="it needs to insert reference index into answer or not",
+        help_text="it needs to insert reference index into answer or not")
+    
     rerank_id = CharField(
         max_length=128,
         null=False,
-        help_text="default rerank model ID",
+        help_text="default rerank model ID")
 
     kb_ids = JSONField(null=False, default=[])
     status = CharField(