Add AST viewer link

Author: pkedy

sidebars.js

@@ -14,7 +14,14 @@
 /** @type {import('@docusaurus/plugin-content-docs').SidebarsConfig} */
 const sidebars = {
   // By default, Docusaurus generates a sidebar from the docs folder structure
-  tutorialSidebar: [{type: 'autogenerated', dirName: '.'}],
+  tutorialSidebar: [
+    {type: 'autogenerated', dirName: '.'},
+    {
+      type: 'link',
+      label: 'AST Viewer',
+      href: 'https://apexlang.github.io/ast-viewer',
+    },
+  ],
 
   // But you can create a sidebar manually
   /*