Docs: Replaced TOC Enhance with Page Index. (#13075)

### What problem does this PR solve?

Replaced TOC Enhance with Page Index.

### Type of change

- [x] Documentation Update

docs/guides/agent/agent_component_reference/retrieval.mdx

@@ -133,6 +133,10 @@ Before enabling this feature, ensure you have properly [constructed a knowledge
 
 Whether to use knowledge graph(s) in the specified dataset(s) during retrieval for multi-hop question answering. When enabled, this would involve iterative searches across entity, relationship, and community report chunks, greatly increasing retrieval time.
 
+### PageIndex
+
+Whether to use the page index structure generated by the large model to enhance retrieval. This approach mimics human information-searching behavior in books.
+
 ### Output
 
 The global variable name for the output of the **Retrieval** component, which can be referenced by other components in the workflow.

docs/guides/dataset/extract_table_of_contents.md

@@ -7,14 +7,14 @@ sidebar_custom_props: {
 ---
 # Extract table of contents
 
-Extract table of contents (TOC) from documents to provide long context RAG and improve retrieval.
+Extract PageIndex, namely table of contents, from documents to provide long context RAG and improve retrieval.
 
 ---
 
-During indexing, this technique uses LLM to extract and generate chapter information, which is added to each chunk to provide sufficient global context. At the retrieval stage, it first uses the chunks matched by search, then supplements missing chunks based on the table of contents structure. This addresses issues caused by chunk fragmentation and insufficient context, improving answer quality.
+During indexing, this technique uses LLM to extract and generate chapter information, which is added to each chunk to provide sufficient global context. At the retrieval stage, it first uses the chunks matched by search, then supplements missing chunks based on the PageIndex (table of contents) structure. This addresses issues caused by chunk fragmentation and insufficient context, improving answer quality.
 
 :::danger WARNING
-Enabling TOC extraction requires significant memory, computational resources, and tokens.
+Enabling PageIndex extraction requires significant memory, computational resources, and tokens.
 :::
 
 ## Prerequisites
@@ -27,15 +27,15 @@ The system's default chat model is used to summarize clustered content. Before p
 
 1. Navigate to the **Configuration** page.
 
-2. Enable **TOC Enhance**.
+2. Enable **PageIndex**.
 
 3. To use this technique during retrieval, do either of the following:
    
-   - In the **Chat setting** panel of your chat app, switch on the **TOC Enhance** toggle.
-   - If you are using an agent, click the **Retrieval** agent component to specify the dataset(s) and switch on the **TOC Enhance** toggle.
+   - In the **Chat setting** panel of your chat app, switch on the **PageIndex** toggle.
+   - If you are using an agent, click the **Retrieval** agent component to specify the dataset(s) and switch on the **Page Index** toggle.
 
 ## Frequently asked questions
 
-### Will previously parsed files be searched using the TOC enhancement feature once I enable `TOC Enhance`?
+### Will previously parsed files be searched using the directory enhancement feature once I enable `PageIndex`?
 
-No. Only files parsed after you enable **TOC Enhance** will be searched using the TOC enhancement feature. To apply this feature to files parsed before enabling **TOC Enhance**, you must reparse them.
+No. Only files parsed after you enable **PageIndex** will be searched using the directory enhancement feature. To apply this feature to files parsed before enabling **PageIndex**, you must reparse them.

docs/guides/memory/_category_.json

@@ -1,6 +1,6 @@
 {
   "label": "Memory",
-  "position": 10,
+  "position": 3.5,
   "link": {
     "type": "generated-index",
     "description": "Guides on using Memory."