mathjax: Update.

layouts/shortcodes/mathjax.html

@@ -1,28 +1,14 @@
-<script type="text/javascript" async
-src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
-MathJax.Hub.Config({
-tex2jax: {
+<script>
+  window.MathJax = {
+    tex: {
       inlineMath: [['$','$'], ['\\(','\\)']],
       displayMath: [['$$','$$']],
       processEscapes: true,
-  processEnvironments: true,
-  skipTags: ['script', 'noscript', 'style', 'textarea', 'pre'],
-  TeX: { equationNumbers: { autoNumber: "AMS" },
-       extensions: ["AMSmath.js", "AMSsymbols.js"] }
+      processEnvironments: true
+    },
+    options: {
+      skipHtmlTags: ['script', 'noscript', 'style', 'textarea', 'pre']
     }
-});
-MathJax.Hub.Queue(function() {
-  // Fix <code> tags after MathJax finishes running. This is a
-  // hack to overcome a shortcoming of Markdown. Discussion at
-  // https://github.com/mojombo/jekyll/issues/199
-  var all = MathJax.Hub.getAllJax(), i;
-  for(i = 0; i < all.length; i += 1) {
-      all[i].SourceElement().parentNode.className += ' has-jax';
-  }
-});
-
-MathJax.Hub.Config({
-// Autonumbering by mathjax
-TeX: { equationNumbers: { autoNumber: "AMS" } }
-});
+  };
 </script>
+<script src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-chtml.min.js" id="MathJax-script"></script>