function custom_editor_script() {
    ?>
    <script type="text/javascript">
        document.addEventListener('DOMContentLoaded', function () {
            if (typeof wp !== 'undefined' && typeof wp.data !== 'undefined') {
                wp.data.subscribe(function () {
                    const blocks = wp.data.select('core/block-editor').getBlocks();
                    blocks.forEach(block => {
                        if (block.name === 'core/footnote') {
                            let newContent = `[${block.attributes.content}]`;
                            if (block.attributes.content !== newContent) {
                                wp.data.dispatch('core/block-editor').updateBlockAttributes(block.clientId, {
                                    content: newContent
                                });
                            }
                        }
                    });
                });
            }
        });
    </script>
    <?php
}
add_action('admin_footer', 'custom_editor_script');