Update docs/configuring-playbook-bot-draupnir.md: add "optoional, recommended" label to the section

Unlike Mjolnir, the step is no longer required. It is optional and recommended on Draupnir, therefore it should be clarified so.

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-playbook-bot-draupnir.md

@@ -72,7 +72,7 @@ Before proceeding to the next step, run the playbook with the following command
 ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,ensure-matrix-users-created
 ```
 
-### Make sure the account is free from rate limiting
+### Make sure the account is free from rate limiting (optional, recommended)
 
 If your homeserver's implementation is Synapse, you will need to prevent it from rate limiting the bot's account. **This is a highly recommended step. If you do not configure it, Draupnir performance will be degraded.**