Add back heading anchors via markdown-it-anchors plugin

realms/__init__.py

@@ -230,6 +230,7 @@ assets.register('main.js',
                 'vendor/handlebars/handlebars.js',
                 'vendor/js-yaml/dist/js-yaml.js',
                 'vendor/markdown-it/dist/markdown-it.js',
+                'vendor/markdown-it-anchor/index.0',
                 'js/html-sanitizer-minified.js',  # don't minify?
                 'vendor/highlightjs/highlight.pack.js',
                 'vendor/parsleyjs/dist/parsley.js',

realms/static/js/mdr.js

@@ -52,6 +52,14 @@ var markdownit = window.markdownit({
 
     return ''; // use external default escaping
   }
+}).use(markdownItAnchor, {
+  level: 1,
+  // slugify: string => string,
+  permalink: false,
+  // renderPermalink: (slug, opts, state, permalink) => {},
+  permalinkClass: 'header-anchor',
+  permalinkSymbol: '¶',
+  permalinkBefore: false
 });
 
 // Markdown Renderer