[DOCS] Adds more details on X-Pack documentation

Author: picandocodigo

docs/overview.asciidoc

@@ -24,14 +24,17 @@ More documentation is hosted in https://github.com/elastic/elasticsearch-ruby[Gi
 [[transport-api]]
 === Transport and API
 
-The `elasticsearch` gem combines two separate Rubygems:
+The `elasticsearch` gem combines three separate Rubygems:
 
-* https://github.com/elastic/elasticsearch-ruby/tree/master/elasticsearch-transport[`elasticsearch-transport`]
+* https://github.com/elastic/elasticsearch-ruby/tree/7.16/elasticsearch-transport[`elasticsearch-transport`]
 provides an HTTP Ruby client for connecting to the {es} cluster,
 
-* https://github.com/elastic/elasticsearch-ruby/tree/master/elasticsearch-api[`elasticsearch-api`]
+* https://github.com/elastic/elasticsearch-ruby/tree/7.16/elasticsearch-api[`elasticsearch-api`]
 provides a Ruby API for the {es} RESTful API.
 
+* https://github.com/elastic/elasticsearch-ruby/tree/7.16/elasticsearch-xpack/[`elasticsearch-xpack`]
+provides a Ruby API for the {es} RESTful API for X-Pack endpoints. Notice that the API endpoints living in `elasticsearch-xpack` will be moved into `elasticsearch-api` in version 8.0.0 and forward. You should be able to keep using `elasticsearch-xpack` and the `xpack` namespace in `7.x` versions. We're running the same tests in `elasticsearch-xpack`, but if you encounter any problems, please let us know https://github.com/elastic/elasticsearch-ruby/issues/1274[in this issue].
+
 Please consult their respective documentation for configuration options and 
 technical details.
 

docs/transport.asciidoc

@@ -11,9 +11,6 @@ data serialization and transport.
 
 It does not handle calling the {es} API.
 
-The library is compatible with Ruby 1.9 or higher and with all versions of {es} 
-since 0.90.
-
 For optimal performance, use a HTTP library which supports persistent 
 ("keep-alive") connections, such as https://github.com/toland/patron[patron] or 
 https://github.com/typhoeus/typhoeus[Typhoeus]. Require the library 
@@ -58,7 +55,7 @@ any configuration:
 require 'elasticsearch/transport'
 
 client = Elasticsearch::Client.new
-response = client.perform_request 'GET', '_cluster/health'
+response = client.perform_request('GET', '_cluster/health')
 # => #<Elasticsearch::Transport::Transport::Response:0x007fc5d506ce38 @status=200, @body={ ... } >
 ```
 
@@ -250,4 +247,4 @@ by injecting it directly.
 
 * The `Elasticsearch::Transport::Transport::Connections::Selector::Base` 
   implementations allow to choose connections from the pool, for example, in a 
-  round-robin or random fashion. You can implement your own selector strategy.
+  round-robin or random fashion. You can implement your own selector strategy.

elasticsearch-xpack/README.md

@@ -15,14 +15,15 @@ A Ruby integration for the [X-Pack extension](https://www.elastic.co/guide/en/x-
 
 Install the package from [Rubygems](https://rubygems.org):
 
-    gem install elasticsearch-api
+    gem install elasticsearch-xpack
 
 ## Usage
 
-If you use the official [Ruby client for Elasticsearch](https://github.com/elastic/elasticsearch-ruby), all the methods will be automatically available:
+If you use the official [Ruby client for Elasticsearch](https://github.com/elastic/elasticsearch-ruby), require the library in your code, and all the methods will be automatically available in the `xpack` namespace:
 
 ```ruby
 require 'elasticsearch'
+require 'elasticsearch/xpack
 
 client = Elasticsearch::Client.new(url: 'http://elastic:changeme@localhost:9200')