Added legacy js client to the doc build (#964)

Author: delvedor

conf.yaml

@@ -351,7 +351,7 @@ contents:
                 title:      JavaScript API
                 prefix:     javascript-api
                 current:    7.x
-                branches:   [ master, 7.x, 6.x, 5.x ]
+                branches:   [ master, 7.x, 6.x, 5.x, 16.x ]
                 index:      docs/index.asciidoc
                 tags:       Clients/JavaScript
                 subject:    Clients