Flesh out about page.

docs/src/parser/nodes/CodeBlock.js

@@ -0,0 +1,19 @@
+const { contentAsText } = require('../helpers')
+
+module.exports = async (doc, rootLevel) => {
+  const { next, level, line, head, tail, match } = doc
+
+  const node = {
+    type: head(),
+    language: tail(),
+    class: '',
+    text: ''
+  }
+
+  while (await next(rootLevel)) {
+    if (match('class')) node.class = tail()
+    else node.text = await contentAsText(doc, rootLevel, true)
+  }
+
+  return node
+}