Update links to reference docs from other files

docs/changelog.asciidoc

@@ -118,8 +118,7 @@ https://www.elastic.co/guide/en/elasticsearch/reference/8.15/release-notes-8.15.
 ===== OpenTelemetry zero-code instrumentation support
 
 For those that use an observability service that supports OpenTelemetry spans, the client will now automatically generate traces for each Elasticsearch request it makes.
-See {jsclient}/observability.html#_opentelemetry[the docs]
-for more information.
+See <<o11y-otel,the docs>> for more information.
 
 [discrete]
 === 8.14.1
@@ -329,7 +328,7 @@ https://www.elastic.co/guide/en/elasticsearch/reference/8.9/release-notes-8.9.0.
 [discrete]
 ===== Allow document to be overwritten in `onDocument` iteratee of bulk helper https://github.com/elastic/elasticsearch-js/pull/1732[#1732]
 
-In the {jsclient}/client-helpers.html#bulk-helper[bulk helper], documents could not be modified before being sent to Elasticsearch. It is now possible to {jsclient}/client-helpers.html#_modifying_a_document_before_operation[modify a document] before sending it.
+In the <<bulk-helper,bulk helper>>, documents could not be modified before being sent to Elasticsearch. It is now possible to <<bulk-modify-doc,modify a document>> before sending it.
 
 [discrete]
 ==== Fixes

docs/examples/bulk.asciidoc

@@ -1,10 +1,10 @@
 [[bulk_examples]]
 === Bulk
 
-With the {jsclient}/api-reference.html#_bulk[`bulk` API], you can perform multiple index/delete operations in a 
+With the <<client.bulk,`bulk` API>>, you can perform multiple index/delete operations in a
 single API call. The `bulk` API significantly increases indexing speed.
 
-NOTE: You can also use the {jsclient}/client-helpers.html[bulk helper].
+NOTE: You can also use the <<bulk-helper,bulk helper>>.
 
 [source,js]
 ----

docs/examples/scroll.asciidoc

@@ -19,7 +19,7 @@ In order to use scrolling, the initial search request should specify the scroll
 parameter in the query string, which tells {es} how long it should keep the
 “search context” alive.
 
-NOTE: Did you know that we provide an helper for sending scroll requests? You can find it {jsclient}/client-helpers.html[here].
+NOTE: Did you know that we provide an helper for sending scroll requests? You can find it <<scroll-search-helper,here>>.
 
 [source,js]
 ----

docs/helpers.asciidoc

@@ -338,6 +338,7 @@ console.log(result)
 ----
 
 [discrete]
+[[bulk-modify-doc]]
 ==== Modifying a document before operation
 
 ~Added~ ~in~ ~`v8.8.2`~

docs/observability.asciidoc

@@ -16,6 +16,7 @@ features.
 All of these observability features are documented below.
 
 [discrete]
+[[o11y-otel]]
 ==== OpenTelemetry
 
 The client supports OpenTelemetry's https://opentelemetry.io/docs/zero-code/js/[zero-code