Updated "Controlling Matrix federation" link

Missing file ending results in 404

docs/configuring-playbook.md

@@ -25,7 +25,7 @@ When you're done with all the configuration you'd like to do, continue with [Ins
 
 - [Enabling Telemetry for your Matrix server](configuring-playbook-telemetry.md) (optional)
 
-- [Controlling Matrix federation](configuring-playbook-federation) (optional)
+- [Controlling Matrix federation](configuring-playbook-federation.md) (optional)
 
 - [Adjusting email-sending settings](configuring-playbook-email.md) (optional)
 
@@ -45,4 +45,4 @@ When you're done with all the configuration you'd like to do, continue with [Ins
 
 - [Setting up Mautrix Telegram bridging](configuring-playbook-bridge-mautrix-telegram.md) (optional)
 
-- [Setting up Mautrix Whatsapp bridging](configuring-playbook-bridge-mautrix-whatsapp.md) (optional)
+- [Setting up Mautrix Whatsapp bridging](configuring-playbook-bridge-mautrix-whatsapp.md) (optional)