style: use padronized comment style on css files

Co-authored-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>
Signed-off-by: David Lima <antdavidlima@gmail.com>

Author: AntDavidLima

css/style.css

@@ -1,5 +1,7 @@
-/* SPDX-FileCopyrightText: 2025 LibreCode coop and contributors */
-/* SPDX-License-Identifier: AGPL-3.0-or-later */
+/**
+ * SPDX-FileCopyrightText: 2025 LibreCode coop and contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
 
 .icon-extract {
 	background-image: url("../img/extracticon.svg");