Update README.rst

Author: kpogromskiy

README.rst

@@ -293,15 +293,15 @@ If you just want to start a single instance of the app and run it directly::
 
     # Add Velas Account Auth Provider
     Append homeserver.yaml with the following:
-<code>
+`
 password_providers:
   - module: "synapse.handlers.vaccount_auth.VaccountAuthProvider"
     config:
       REDIS_HOSTNAME: "redis"
       REDIS_PASS: "development"
       REDIS_REPLICATION_MODE: "master"
       REDIS_PORT: 6379
-</code>
+`
     # Start the app
     python -m synapse.app.homeserver --config-path homeserver.yaml