Recent history exchange: README.md updates

(cherry picked from commit 1afe656)

Author: michaelklishin

deps/rabbitmq_recent_history_exchange/README.md

@@ -2,57 +2,29 @@
 
 Keeps track of the last 20 messages that passed through the exchange. Every time a queue is bound to the exchange it delivers that last 20 messages to them. This is useful for implementing a very simple __Chat History__ where clients that join the conversation can get the latest messages.
 
-Exchange Type: `x-recent-history`
+Exchange yype: `x-recent-history`.
 
 ## Installation ##
 
-### RabbitMQ 3.6.0 or later
+This plugin ships with RabbitMQ. 
 
-As of RabbitMQ `3.6.0` this plugin is included into the RabbitMQ distribution.
-
-Enable it with the following command:
-
-```bash
-rabbitmq-plugins enable rabbitmq_recent_history_exchange
-```
-
-### With Earlier Versions
-
-Install the corresponding .ez files from our
-[Community Plugins archive](https://www.rabbitmq.com/community-plugins/)..
-
-Then run the following command:
+Like all other plugins, it must be enabled before it can be used:
 
 ```bash
-rabbitmq-plugins enable rabbitmq_recent_history_exchange
+[sudo] rabbitmq-plugins enable rabbitmq_recent_history_exchange
 ```
 
-## Building from Source
-
-Please see [RabbitMQ Plugin Development guide](https://www.rabbitmq.com/plugin-development.html).
-
-To build the plugin:
-
-    git clone git://github.com/rabbitmq/rabbitmq-recent-history-exchange.git
-    cd rabbitmq-recent-history-exchange
-    make
-
-Then copy all the `*.ez` files inside the `plugins` folder to the [RabbitMQ plugins directory](https://www.rabbitmq.com/relocate.html)
-and enable the plugin:
-
-    [sudo] rabbitmq-plugins enable rabbitmq_recent_history_exchange
-
 ## Usage ##
 
-### Creating an exchange  ###
+### Creating an exchange
 
 To create a _recent history exchange_, just declare an exchange providing the type `"x-recent-history"`.
 
 ```java
 channel.exchangeDeclare("logs", "x-recent-history");
 ```
 
-### Providing a custom history length ###
+### Providing a custom history length
 
 Typically this exchange will store the latest 20 messages sent over
 the exchange. If you want to set a different cache length, then you
@@ -67,13 +39,13 @@ args.put("x-recent-history-length", 60);
 channel.exchangeDeclare("rh", "x-recent-history", false, false, args);
 ```
 
-### Preventing some messages from being stored ###
+### Preventing some messages from being stored
 
 In case you would like to not store certain messages, just
 add the header `"x-recent-history-no-store"` with the value `true` to
 the message.
 
-## Disabling the Plugin ##
+## Disabling the Plugin
 
 A future version of RabbitMQ will allow users to disable plugins. When
 you disable this plugin, it will delete all the cached messages.