Synchronize documentation. (#438)

Co-authored-by: RAGFlow Curator <infinitydocs.curator@users.noreply.github.com>

Author: infinityCurator

website/docs/references/http_api_reference.md

@@ -1840,7 +1840,7 @@ Retrieves chunks from specified datasets.
   - `"highlight"`: `boolean`
   - `"cross_languages"`: `list[string]`
   - `"metadata_condition"`: `object`
-
+  - `"use_kg"`: `boolean`
 ##### Request example
 
 ```bash
@@ -1888,6 +1888,8 @@ curl --request POST \
   The weight of vector cosine similarity. Defaults to `0.3`. If x represents the weight of vector cosine similarity, then (1 - x) is the term similarity weight.
 - `"top_k"`: (*Body parameter*), `integer`  
   The number of chunks engaged in vector cosine computation. Defaults to `1024`.
+- `"use_kg"`: (*Body parameter*), `boolean`  
+  The search includes text chunks related to the knowledge graph of the selected dataset to handle complex multi-hop queries. Defaults to `False`.
 - `"rerank_id"`: (*Body parameter*), `integer`  
   The ID of the rerank model.
 - `"keyword"`: (*Body parameter*), `boolean`