markdown export from URL (#5830)

* Add Markdown export of any doc page by appending `.md` to the URL
* New "View as Markdown" dropdown menu from the "copy page" button

documentation/docusaurus.config.ts

@@ -29,7 +29,12 @@ const config: Config = {
   projectName: "goose", // Usually your repo name.
 
   onBrokenLinks: "throw",
-  onBrokenMarkdownLinks: "warn",
+  
+  markdown: {
+    hooks: {
+      onBrokenMarkdownLinks: "warn",
+    },
+  },
 
   // Even if you don't use internationalization, you can use this field to set
   // useful metadata like html lang. For example, if your site is Chinese, you
@@ -315,6 +320,12 @@ const config: Config = {
       },
     ],
     tailwindPlugin,
+    [
+      require.resolve("./plugins/markdown-export.cjs"),
+      {
+        enabled: true,
+      },
+    ],
   ],
   themes: ["@inkeep/docusaurus/chatButton", "@inkeep/docusaurus/searchBar"],
   themeConfig: {