Update validate_config.yml files: edit the banner message for variables name

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

roles/custom/matrix-bridge-appservice-discord/tasks/validate_config.yml

@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2019 - 2024 Slavi Pantaleev
+# SPDX-FileCopyrightText: 2025 Suguru Hirahara
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
@@ -22,7 +23,7 @@
   ansible.builtin.fail:
     msg: >-
       Your configuration contains a variable, which now has a different name.
-      Please change your configuration to rename the variable (`{{ item.old }}` -> `{{ item.new }}`).
+      Please rename the variable (`{{ item.old }}` -> `{{ item.new }}`) on your configuration file (vars.yml).
   when: "item.old in vars"
   with_items:
     - {'old': 'matrix_appservice_discord_container_expose_client_server_api_port', 'new': '<superseded by matrix_appservice_discord_container_http_host_bind_port>'}