Announce synapse-usage-exporter support

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3442

docs/configuring-playbook-prometheus-grafana.md

@@ -121,6 +121,7 @@ scrape_configs:
 
 ## More information
 
+- [Enabling synapse-usage-exporter for Synapse usage statistics](configuring-playbook-synapse-usage-exporter.md)
 - [Understanding Synapse Performance Issues Through Grafana Graphs](https://element-hq.github.io/synapse/latest/usage/administration/understanding_synapse_through_grafana_graphs.html) at the Synapse Github Wiki
 - [The Prometheus scraping rules](https://github.com/element-hq/synapse/tree/master/contrib/prometheus) (we use v2)
 - [The Synapse Grafana dashboard](https://github.com/element-hq/synapse/tree/master/contrib/grafana)

docs/configuring-playbook-synapse.md

@@ -161,4 +161,6 @@ Due to this, it's recommended to only store and maintain template files in your
 
 This playbook allows you to enable Synapse metrics, which can provide insight into the performance and activity of Synapse.
 
-To enable Synapse metrics see [`configuring-playbook-prometheus-grafana.md`](./configuring-playbook-prometheus-grafana.md)
+To enable Synapse runtime metrics see: [Enabling metrics and graphs (Prometheus, Grafana) for your Matrix server](configuring-playbook-prometheus-grafana.md)
+
+To enable Synapse usage metrics, see: [Enabling synapse-usage-exporter for Synapse usage statistics](configuring-playbook-synapse-usage-exporter.md)

docs/configuring-playbook.md

@@ -42,6 +42,8 @@ When you're done with all the configuration you'd like to do, continue with [Ins
 
 - [Enabling metrics and graphs (Prometheus, Grafana) for your Matrix server](configuring-playbook-prometheus-grafana.md) (optional)
 
+- [Enabling synapse-usage-exporter for Synapse usage statistics](configuring-playbook-synapse-usage-exporter.md) (optional)
+
 ### Core service adjustments
 
 - Homeserver configuration: