Update docs/configuring-playbook-bridge-appservice-slack.md: emphasize the unavailability without a classic Slack application

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

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

@@ -2,7 +2,7 @@
 
 **Notes**:
 - Bridging to [Slack](https://slack.com) can also happen via the [mx-puppet-slack](configuring-playbook-bridge-mx-puppet-slack.md) and [mautrix-slack](configuring-playbook-bridge-mautrix-slack.md) bridges supported by the playbook.
-- Currently (as of November, 2024) this component is not available for new installation unless you have already created a classic Slack application (which the bridge makes use of in order to enable bridging between Slack and Matrix), because the creation of classic Slack applications has been discontinued since June 4 2024. The author of the bridge claims [here](https://github.com/matrix-org/matrix-appservice-slack/issues/789#issuecomment-2172947787) that he plans to support the modern Slack application and until then "the best (and only) option for new installations is to use the webhook bridging".
+- Currently (as of November, 2024) **this component is not available for new installation unless you have already created a classic Slack application** (which the bridge makes use of in order to enable bridging between Slack and Matrix), because the creation of classic Slack applications has been discontinued since June 4 2024. The author of the bridge claims [here](https://github.com/matrix-org/matrix-appservice-slack/issues/789#issuecomment-2172947787) that he plans to support the modern Slack application and until then "the best (and only) option for new installations is to use the webhook bridging".
 
 The playbook can install and configure [matrix-appservice-slack](https://github.com/matrix-org/matrix-appservice-slack) for you.