single.php

the_reverse_post_navigation( array(
	'prev_text' => '<span class="screen-reader-text">' . __( 'Previous Post', 'twentyseventeen' ) . '</span><span aria-hidden="true" class="nav-subtitle">' . __( 'Previous', 'twentyseventeen' ) . '</span> <span class="nav-title"><span class="nav-title-icon-wrapper">' . twentyseventeen_get_svg( array( 'icon' => 'arrow-left' ) ) . '</span>%title</span>',
	'next_text' => '<span class="screen-reader-text">' . __( 'Next Post', 'twentyseventeen' ) . '</span><span aria-hidden="true" class="nav-subtitle">' . __( 'Next', 'twentyseventeen' ) . '</span> <span class="nav-title">%title<span class="nav-title-icon-wrapper">' . twentyseventeen_get_svg( array( 'icon' => 'arrow-right' ) ) . '</span></span>',
) );

the_reverse_post_navigation

function the_reverse_post_navigation( $args = array() ) {
    $args = wp_parse_args( $args, array(
        'prev_text'          => '%title',
        'next_text'          => '%title',
        'in_same_term'       => false,
        'excluded_terms'     => '',
        'taxonomy'           => 'category',
        'screen_reader_text' => __( 'Post navigation' ),
    ) );

    $navigation = '';

    $previous = get_next_post_link(
        '<div class="nav-previous">%link</div>',
        $args['prev_text'],
        $args['in_same_term'],
        $args['excluded_terms'],
        $args['taxonomy']
    );

    $next = get_previous_post_link(
        '<div class="nav-next">%link</div>',
        $args['next_text'],
        $args['in_same_term'],
        $args['excluded_terms'],
        $args['taxonomy']
    );

    // Only add markup if there's somewhere to navigate to.
    if ( $previous || $next ) {
        $navigation = _navigation_markup( $previous . $next, 'post-navigation', $args['screen_reader_text'] );
    }

    echo $navigation;
}