WIP - add extractor, generate snippet_data

node_modules/remark-stringify/lib/visitors/footnote-definition.js

@@ -0,0 +1,12 @@
+'use strict';
+
+var repeat = require('repeat-string');
+
+module.exports = footnoteDefinition;
+
+function footnoteDefinition(node) {
+  var id = node.identifier.toLowerCase();
+  var content = this.all(node).join('\n\n' + repeat(' ', 4));
+
+  return '[^' + id + ']: ' + content;
+}