Format comment header number

Apparently, some stories actually break a thousand. Good for them.

includes/functions/comments/_comments_threads.php

@@ -102,7 +102,7 @@ if ( ! function_exists( 'fictioneer_comment_header' ) ) {
         <?php echo
           sprintf(
             __( '<span class="fictioneer-comments__total">%1$s</span> <span>%2$s</span>' ),
-            $comment_count,
+            number_format_i18n( $comment_count ),
             _n( 'Comment', 'Comments', $comment_count, 'fictioneer' )
           )
         ?>

includes/functions/hooks/_story_hooks.php

@@ -805,7 +805,7 @@ function fictioneer_story_comments( $args ) {
             $story['comment_count'],
             'fictioneer'
           ),
-          $story['comment_count']
+          number_format_i18n( $story['comment_count'] )
         );
       ?></h2>
     <?php endif; ?>