client: Change the icon of the "Formatting" tab

src/public/app/widgets/ribbon_widgets/classic_editor_toolbar.js

@@ -60,7 +60,7 @@ export default class ClassicEditorToolbar extends NoteContextAwareWidget {
             show: await this.#shouldDisplay(),
             activate: true,
             title: t("classic_editor_toolbar.title"),
-            icon: "bx bx-edit-alt"
+            icon: "bx bx-text"
         };
     }