Cross-link similar bridges

docs/configuring-playbook-bridge-appservice-irc.md

@@ -1,6 +1,8 @@
 # Setting up Appservice IRC (optional)
 
-The playbook can install and configure [matrix-appservice-irc](https://github.com/matrix-org/matrix-appservice-irc) for you.
+**Note**: bridging to [IRC](https://en.wikipedia.org/wiki/Internet_Relay_Chat) can also happen via the [Heisenbridge](configuring-playbook-bridge-heisenbridge.md) bridge supported by the playbook.
+
+The playbook can install and configure the [matrix-appservice-irc](https://github.com/matrix-org/matrix-appservice-irc) bridge for you.
 
 See the project's [documentation](https://github.com/matrix-org/matrix-appservice-irc/blob/master/HOWTO.md) to learn what it does and why it might be useful to you.
 

docs/configuring-playbook-bridge-appservice-slack.md

@@ -1,5 +1,7 @@
 # Setting up Appservice Slack (optional)
 
+**Note**: bridging to [Slack](https://slack.com) can also happen via the [mx-puppet-slack](configuring-playbook-bridge-mx-puppet-slack.md) bridge supported by the playbook.
+
 The playbook can install and configure [matrix-appservice-slack](https://github.com/matrix-org/matrix-appservice-slack) for you.
 
 See the project's [documentation](https://github.com/matrix-org/matrix-appservice-slack/blob/master/README.md) to learn what it does and why it might be useful to you.

docs/configuring-playbook-bridge-heisenbridge.md

@@ -1,6 +1,8 @@
 # Setting up Heisenbridge (optional)
 
-The playbook can install and configure [Heisenbridge](https://github.com/hifi/heisenbridge) - the bouncer-style IRC bridge for you.
+**Note**: bridging to [IRC](https://en.wikipedia.org/wiki/Internet_Relay_Chat) can also happen via the [matrix-appservice-irc](configuring-playbook-bridge-appservice-irc.md) bridge supported by the playbook.
+
+The playbook can install and configure [Heisenbridge](https://github.com/hifi/heisenbridge) - the bouncer-style [IRC](https://en.wikipedia.org/wiki/Internet_Relay_Chat) bridge for you.
 
 See the project's [README](https://github.com/hifi/heisenbridge/blob/master/README.md) to learn what it does and why it might be useful to you.
 

docs/configuring-playbook-bridge-mx-puppet-slack.md

@@ -1,5 +1,7 @@
 # Setting up MX Puppet Slack (optional)
 
+**Note**: bridging to [Slack](https://slack.com) can also happen via the [matrix-appservice-slack](configuring-playbook-bridge-appservice-slack.md) bridge supported by the playbook.
+
 The playbook can install and configure
 [mx-puppet-slack](https://github.com/Sorunome/mx-puppet-slack) for you.