Split retrievers docs and redirect anchors (#131385)

Author: leemthompo

docs/redirects.yml

@@ -1,3 +1,25 @@
 redirects:
-# Related to https://github.com/elastic/elasticsearch/pull/130716/
-  'reference/query-languages/eql/eql-ex-threat-detection.md': 'docs-content://explore-analyze/query-filter/languages/example-detect-threats-with-eql.md'
+  # Related to https://github.com/elastic/elasticsearch/pull/130716/
+  'reference/query-languages/eql/eql-ex-threat-detection.md': 'docs-content://explore-analyze/query-filter/languages/example-detect-threats-with-eql.md'
+  
+  # https://github.com/elastic/elasticsearch/pull/131385
+  'reference/elasticsearch/rest-apis/retrievers.md':
+    to: 'reference/elasticsearch/rest-apis/retrievers.md'
+    anchors: {} # pass-through unlisted anchors in the `many` ruleset
+    many:
+      - to: 'reference/elasticsearch/rest-apis/retrievers/standard-retriever.md'
+        anchors: {'standard-retriever'}
+      - to: 'reference/elasticsearch/rest-apis/retrievers/knn-retriever.md'
+        anchors: {'knn-retriever'}
+      - to: 'reference/elasticsearch/rest-apis/retrievers/linear-retriever.md'
+        anchors: {'linear-retriever'}
+      - to: 'reference/elasticsearch/rest-apis/retrievers/rrf-retriever.md'
+        anchors: {'rrf-retriever'}
+      - to: 'reference/elasticsearch/rest-apis/retrievers/rescorer-retriever.md'
+        anchors: {'rescorer-retriever'}
+      - to: 'reference/elasticsearch/rest-apis/retrievers/text-similarity-reranker-retriever.md'
+        anchors: {'text-similarity-reranker-retriever'}
+      - to: 'reference/elasticsearch/rest-apis/retrievers/rule-retriever.md'
+        anchors: {'rule-retriever'}
+      - to: 'reference/elasticsearch/rest-apis/retrievers/pinned-retriever.md'
+        anchors: {'pinned-retriever'}

docs/reference/elasticsearch/rest-apis/reciprocal-rank-fusion.md

@@ -34,7 +34,7 @@ For the most up-to-date API details, refer to [Search APIs](https://www.elastic.
 ::::
 
 
-You can use RRF as part of a [search](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-search) to combine and rank documents using separate sets of top documents (result sets) from a combination of [child retrievers](/reference/elasticsearch/rest-apis/retrievers.md) using an [RRF retriever](/reference/elasticsearch/rest-apis/retrievers.md#rrf-retriever). A minimum of **two** child retrievers is required for ranking.
+You can use RRF as part of a [search](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-search) to combine and rank documents using separate sets of top documents (result sets) from a combination of [child retrievers](/reference/elasticsearch/rest-apis/retrievers.md) using an [RRF retriever](/reference/elasticsearch/rest-apis/retrievers/rrf-retriever.md). A minimum of **two** child retrievers is required for ranking.
 
 An RRF retriever is an optional object defined as part of a search request’s [retriever parameter](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-search#request-body-retriever). The RRF retriever object contains the following parameters: