Formatting request

Thanks for your work.

In your function function manage_subtitle_columns_content could you consider wrapping the subtitle in . Makes for a better optical view in the admin back-end.

public static function manage_subtitle_columns_content( $column_name, $post_id ) {
  if ( $column_name == 'wps_subtitle' ) {
     $subtitle = new WP_Subtitle( $post_id );
     echo '<strong><span data-wps_subtitle="' . esc_attr( $subtitle->get_subtitle() ) . '">' . esc_html( $subtitle->get_subtitle() ) . '</span></strong>';
  }
}