amend docs

docs/configuring-playbook-bridge-hookshot.md

@@ -25,7 +25,7 @@ Finally, run the playbook (see [installing](installing.md)).
 
 ### End-to-bridge endcryption
 
-1. Enable by setting `: true`
+1. Enable by setting `matrix_hookshot_experimental_encryption_enabled: true`
 
 If the crypto store has become corrupted, reset it by running `ansible-playbook -i inventory/hosts setup.yml -K --tags=reset-hookshot-encryption`.