Restore all plugins because they were not the cause.

greenwood.config.js

@@ -41,7 +41,7 @@ export default {
   // would be nice if we could customize these plugins, like appending the autolink headings
   // https://github.com/ProjectEvergreen/greenwood/issues/1247
   markdown: {
-    plugins: [],
+    plugins: ["@mapbox/rehype-prism", "rehype-slug", "rehype-autolink-headings", "remark-github"],
   },
 
   plugins: [