[DOCS] Updates compatibility matrix

Author: picandocodigo

README.md

@@ -55,9 +55,7 @@ see the **[elasticsearch-rails](https://github.com/elasticsearch/elasticsearch-r
 
 We follow Ruby’s own maintenance policy and officially support all currently maintained versions per [Ruby Maintenance Branches](https://www.ruby-lang.org/en/downloads/branches/).
 
-Elastic language clients are guaranteed to be able to communicate with Elasticsearch or Elastic solutions running on the same major version and greater or equal minor version.
-
-Language clients are forward compatible; meaning that clients support communicating with greater minor versions of Elasticsearch. Elastic language clients are not guaranteed to be backward compatible.
+Language clients are forward compatible; meaning that clients support communicating with greater minor versions of Elasticsearch. Elastic language clients are also backwards compatible with lesser supported minor Elasticsearch versions.
 
 The gem's version numbers follow Elasticsearch's major versions. The `master` branch is compatible with the Elasticsearch `master` branch, which is the next major version.
 

docs/installation.asciidoc

@@ -40,9 +40,7 @@ gem 'elasticsearch', '~> 7.0'
 
 The {es} client is compatible with currently maintained Ruby versions. We follow Ruby’s own maintenance policy and officially support all currently maintained versions per https://www.ruby-lang.org/en/downloads/branches/[Ruby Maintenance Branches].
 
-Elastic language clients are guaranteed to be able to communicate with {es} or Elastic solutions running on the same major version and greater or equal minor version.
-
-Language clients are forward compatible; meaning that clients support communicating with greater minor versions of {es}. Elastic language clients are not guaranteed to be backward compatible.
+Language clients are forward compatible; meaning that clients support communicating with greater minor versions of {es}. Elastic language clients are also backwards compatible with lesser supported minor {es} versions.
 
 |===
 | Gem Version   |   | {es} Version

docs/overview.asciidoc

@@ -5,11 +5,7 @@ The `elasticsearch` http://rubygems.org/gems/elasticsearch[Rubygem] provides a
 low-level client for communicating with an {es} cluster, fully compatible with 
 other official clients.
 
-Full documentation is hosted at 
-https://github.com/elastic/elasticsearch-ruby[Github] and 
-http://rubydoc.info/gems/elasticsearch[RubyDoc]. This documentation provides 
-only an overview of features.
-
+More documentation is hosted in https://github.com/elastic/elasticsearch-ruby[Github] and http://rubydoc.info/gems/elasticsearch[RubyDoc].
 
 [discrete]
 === Features