[SPARK-60281][INFRA] Upgrade AnchorJS to v5.0.0

docs/_layouts/global.html

@@ -196,7 +196,18 @@ <h1 class="title">{{ page.title }}</h1>
         <script src="{{ rel_path_to_root }}js/vendor/jquery.min.js"></script>
         <script src="{{ rel_path_to_root }}js/vendor/bootstrap.bundle.min.js"></script>
 
-        <script src="{{ rel_path_to_root }}js/vendor/anchor.min.js"></script>
+        <script src="{{ rel_path_to_root }}js/vendor/anchor.min.js">
+            // Keep the version of AnchorJS used here in sync with what's used on the main website.
+            // See: https://github.com/apache/spark-website/blob/asf-site/js/vendor/anchor.min.js
+        </script>
+        <script>
+            // Display anchor links when hovering over headings.
+            // See: https://www.bryanbraun.com/anchorjs/
+            anchors.options = { placement: 'right' };
+            // Note: AnchorJS 4.0+ excludes h1 from the default selector, but many
+            // Spark doc pages use h1 for section headings, so we include it explicitly.
+            anchors.add('h1, h2, h3, h4, h5, h6');
+        </script>
         <script src="{{ rel_path_to_root}}js/main.js"></script>
 
         <script type="text/javascript" src="{{ rel_path_to_root }}js/vendor/docsearch.min.js"></script>

docs/js/main.js

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-/* global $, anchors */
+/* global $ */
 
 /* Custom JavaScript code in the MarkDown docs */
 
@@ -89,12 +89,6 @@ function codeTabs() {
 
 $(function() {
   codeTabs();
-  // Display anchor links when hovering over headers. For documentation of the
-  // configuration options, see the AnchorJS documentation.
-  anchors.options = {
-    placement: 'right'
-  };
-  anchors.add();
 
   // Make dropdown menus in nav bars show on hover instead of click
   // using solution at https://webdesign.tutsplus.com/tutorials/how-

licenses/LICENSE-AnchorJS.txt

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) <year> <copyright holders>
+Copyright (c) 2023 Bryan Braun
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal