All: Limit 'comment-reply' script to posts with comments open

WordPress default themes do this since at least twentynineteenn (2019)
since it doesn't have a purpose on posts even if they had old comments
that use threads since the script is to help author new comments.

Also turn it off globally by default to reflect current reality since
not even the blog had this feature enabled during the time where
comments were used.

Author: Krinkle

sites.php

@@ -369,6 +369,13 @@ function jquery_default_site_options() {
 		'blogdescription' => '',
 		'permalink_structure' => '/%postname%/',
 		'use_smilies' => 0,
+		// The one site where comments are sometimes enabled (blog.jquery.com)
+		// has always had thread_comments turned off.
+		//
+		// Oher sites like api.jquery.com implement their pages as posts,
+		// but naturally don't support comments at all. Turn this off to
+		// remove the WordPress comment-reply script from pages by default.
+		'thread_comments' => 0,
 	);
 
 }

themes/jquery/header.php

@@ -29,7 +29,7 @@
 	<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.css" />
 	<link rel="stylesheet" href="<?php echo get_template_directory_uri(); ?>/css/docsearch.css">
 <?php
-	if ( is_singular() && get_option( 'thread_comments' ) ) {
+	if ( get_option( 'thread_comments' ) && comments_open() ) {
 		wp_enqueue_script( 'comment-reply' );
 	}