Improve sidebar UI for 'Hide SimpleTOC' option

Enhanced the sidebar sub-menu for the 'Hide SimpleTOC' option by wrapping the RadioControl in a styled div for better visual separation and clarity. Updated the readme to document this UI improvement.

Author: mtoensing

build/index.asset.php

@@ -1 +1 @@
-<?php return array('dependencies' => array('react-jsx-runtime', 'wp-block-editor', 'wp-blocks', 'wp-components', 'wp-data', 'wp-editor', 'wp-element', 'wp-i18n', 'wp-primitives', 'wp-server-side-render'), 'version' => '2a31ee7f45c8d21c123b');
+<?php return array('dependencies' => array('react-jsx-runtime', 'wp-block-editor', 'wp-blocks', 'wp-components', 'wp-data', 'wp-editor', 'wp-element', 'wp-i18n', 'wp-primitives', 'wp-server-side-render'), 'version' => 'e814a32c62b5cfd58def');