Update documentation for RabbitMQ Prometheus family types (#20155)

* update documentation about RabbitMQ family types

* Update rabbitmq/README.md

Co-authored-by: Jen Gilbert <jen.gilbert@datadoghq.com>

---------

Co-authored-by: Jen Gilbert <jen.gilbert@datadoghq.com>

Author: robcarlan-datadog

rabbitmq/README.md

@@ -38,15 +38,14 @@ Configure the `prometheus_plugin` section in your instance configuration. When u
        url: http://<HOST>:15692
  ```
 
- This enables scraping of the [`/metrics` endpoint][20] on one RabbitMQ node. Datadog can also collect data from the [`/metrics/detailed` endpoint][22].
-
- ```yaml
+ This enables scraping of the [`/metrics` endpoint][20] on one RabbitMQ node. Datadog can also collect data from the [`/metrics/detailed` endpoint][22]. The metrics collected will depend on which families are included.
+```yaml
  instances:
    - prometheus_plugin:
        url: http://<HOST>:15692
-       unaggregated_endpoint: detailed?family=queue_coarse_metrics
+       unaggregated_endpoint: detailed?family=queue_coarse_metrics&family=queue_consumer_count&family=channel_exchange_metrics&family=channel_queue_exchange_metrics&family=node_coarse_metrics
  ```
- This enables scraping of the [`/metrics/detailed` endpoint][22] to collect queue coarse metrics.
+This configuration collects metrics for each queue, exchange, and node. See the [`/metrics/detailed` API documentation][22] for more information on the metrics provided by each family.
 
 ##### [RabbitMQ Management Plugin][4].
 
@@ -169,7 +168,7 @@ See [service_checks.json][14] for a list of service checks provided by this inte
 The Prometheus Plugin exposes a different set of metrics from the Management Plugin.
 Here is what to be aware of as you migrate from the Management to the Prometheus Plugin.
 
-- Look up your metrics in [this table][23]. If a metric's description contains an `[OpenMetricsV2]` tag, then it is available in the Prometheus Plugin. Metrics available only in the Management Plugin do not have any tags in their descriptions.
+- Look up your metrics in [this table][23]. If a metric's description contains an `[OpenMetrics]` tag, then it is available in the Prometheus Plugin. Metrics available only in the Management Plugin do not have any tags in their descriptions.
 - Any dashboards and monitors using Management Plugin metrics do not function. Switch to the dashboards and monitors marked as *OpenMetrics Version*.
 - The default configuration collects aggregated metrics. This means, for example, that there are no metrics tagged by queue. Configure the option `prometheus_plugin.unaggregated_endpoint` to get metrics without aggregation.
 - The `rabbitmq.status` service check is replaced by `rabbitmq.openmetrics.health`. The service check `rabbitmq.aliveness` has no equivalent in the Prometheus Plugin.