[DOCS] Change 'X-Pack APIs' section to 'REST APIs' (#43451)

client/rest-high-level/src/main/java/org/elasticsearch/client/XPackClient.java

@@ -35,8 +35,8 @@ import static java.util.Collections.emptySet;
  * default distribution of Elasticsearch. All of these APIs will 404 if run
  * against the OSS distribution of Elasticsearch.
  * <p>
- * See the <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/xpack-api.html">
+ * See the <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/rest-apis.html">
- * X-Pack APIs on elastic.co</a> for more information.
+ * REST APIs on elastic.co</a> for more information.
  */
 public final class XPackClient {
 

docs/reference/index.asciidoc

@@ -69,8 +69,6 @@ include::frozen-indices.asciidoc[]
 
 include::administering.asciidoc[]
 
-include::rest-api/index.asciidoc[]
-
 include::commands/index.asciidoc[]
 
 :edit_url:
@@ -80,6 +78,8 @@ include::testing.asciidoc[]
 
 include::glossary.asciidoc[]
 
+include::rest-api/index.asciidoc[]
+
 include::release-notes/highlights.asciidoc[]
 
 include::migration/index.asciidoc[]

docs/reference/redirects.asciidoc

@@ -602,3 +602,8 @@ See <<faster-phrase-queries>>.
 [role="exclude",id="_faster_prefix_queries_with_literal_index_prefixes_literal.html"]
 
 See <<faster-prefix-queries>>.
+
+[role="exclude",id="xpack-api"]
+=== X-Pack APIs
+
+{es} {xpack} APIs are now documented in <<rest-apis, REST APIs>>. 

docs/reference/rest-api/index.asciidoc

@@ -1,11 +1,14 @@
-[role="xpack"]
+[[rest-apis]]
-[[xpack-api]]
+= REST APIs
-= {xpack} APIs
 
 [partintro]
 --
-{xpack} exposes REST APIs that are used by the UI components and can be called
+{es} exposes REST APIs that are used by the UI components and can be called
-directly to configure and access {xpack} features.
+directly to configure and access {es} features.
+
+[NOTE]
+We are working on including more {es} APIs in this section. Some content might
+not be included yet.
 
 * <<info-api,Info API>>
 * <<ccr-apis,{ccr-cap} APIs>>