Fix yamllint-reported errors in matrix-email2matrix

roles/custom/matrix-email2matrix/tasks/validate_config.yml

@@ -1,6 +1,6 @@
 ---
 
-- name: Fail if no mappings
+- name: Fail if no email2matrix mappings
   ansible.builtin.fail:
     msg: >
       You need to define at least one mapping in `matrix_email2matrix_matrix_mappings` for enabling Email2Matrix.
@@ -13,5 +13,3 @@
   when: "item.when | bool and vars[item.name] == ''"
   with_items:
     - {'name': 'matrix_email2matrix_container_network', when: true}
-
-