Docs: Reorganised the search-shards API docs

docs/reference/search.asciidoc

@@ -83,10 +83,12 @@ include::search/request-body.asciidoc[]
 
 include::search/search-template.asciidoc[]
 
-include::search/facets.asciidoc[]
+include::request/search-shards.asciidoc[]
 
 include::search/aggregations.asciidoc[]
 
+include::search/facets.asciidoc[]
+
 include::search/suggesters.asciidoc[]
 
 include::search/multi-search.asciidoc[]