wp/app/themes/twentysixteen/singular.php

<?php
/**
 * The template for displaying all pages, single posts and attachments
 *
 * This is a new template file that WordPress introduced in
 * version 4.3. Note that it uses conditional logic to display
 * different content based on the post type.
 *
 * @link https://codex.wordpress.org/Template_Hierarchy
 *
 * @package WordPress
 * @subpackage Twenty_Sixteen
 * @since Twenty Sixteen 1.0
 */

get_header(); ?>

<div id="primary" class="content-area">
	<main id="main" class="site-main" role="main">
		<?php
		// Start the loop.
		while ( have_posts() ) : the_post();

			// Include the page content template.
			if ( is_singular( 'page' ) ) {
				get_template_part( 'template-parts/content', 'page' );
			} else {
				get_template_part( 'template-parts/content', 'single' );
			}

			// If comments are open or we have at least one comment, load up the comment template.
			if ( comments_open() || get_comments_number() ) {
				comments_template();
			}

			if ( is_singular( 'attachment' ) ) {
				// Parent post navigation
				the_post_navigation( array(
					'prev_text' => _x( '<span class="meta-nav">Published in</span><span class="post-title">%title</span>', 'Parent post link', 'twentysixteen' ),
				) );
			} elseif ( is_singular( 'post' ) ) {
				// Previous/next post navigation.
				the_post_navigation( array(
					'next_text' => '<span class="meta-nav" aria-hidden="true">' . __( 'Next', 'twentysixteen' ) . '</span> ' .
						'<span class="screen-reader-text">' . __( 'Next post:', 'twentysixteen' ) . '</span> ' .
						'<span class="post-title">%title</span>',
					'prev_text' => '<span class="meta-nav" aria-hidden="true">' . __( 'Previous', 'twentysixteen' ) . '</span> ' .
						'<span class="screen-reader-text">' . __( 'Previous post:', 'twentysixteen' ) . '</span> ' .
						'<span class="post-title">%title</span>',
				) );
			}

			// End of the loop.
		endwhile;
		?>

	</main><!-- .site-main -->

	<?php get_sidebar( 'content-bottom' ); ?>

</div><!-- .content-area -->

<?php get_sidebar(); ?>
<?php get_footer(); ?>