[DOCS] High Level Client: fix index items order

Also group APIs under single document, multi-document and search

docs/java-rest/high-level/apis.asciidoc

@@ -2,18 +2,16 @@
 
 The Java High Level REST Client supports the following APIs:
 
+.Single document APIs
 * <<java-rest-high-document-index>>
-
 * <<java-rest-high-document-get>>
-
 * <<java-rest-high-document-delete>>
-
 * Update API
 
+.Multi-document APIs
 * <<java-rest-high-document-bulk>>
 
+.Search APIs
 * Search API
-
 * Search Scroll API
-
 * Clear Scroll API

docs/java-rest/high-level/apis/index.asciidoc

@@ -1,9 +1,9 @@
 :doc-tests: {docdir}/../../client/rest-high-level/src/test/java/org/elasticsearch/client/documentation
 
 include::_index.asciidoc[]
-include::update.asciidoc[]
 include::get.asciidoc[]
 include::delete.asciidoc[]
+include::update.asciidoc[]
 include::bulk.asciidoc[]
 
 :doc-tests!: