Include placeholders in translator comments.

See #31857.

git-svn-id: https://develop.svn.wordpress.org/trunk@34304 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/comment.php

@@ -183,7 +183,7 @@ if ( $comment->comment_approved != '0' ) { // if not unapproved
 			$parent_link = esc_url( get_comment_link( $parent ) );
 			$name        = get_comment_author( $parent );
 			printf(
-				/* translators: comment link */
+				/* translators: %s: comment link */
 				' | ' . __( 'In reply to %s.' ),
 				'<a href="' . $parent_link . '">' . $name . '</a>'
 			);