Add comments for auto API docs

packages/menus/README.md

@@ -14,4 +14,18 @@ npm install @wordpress/menus
 
 _This package assumes that your code will run in an **ES2015+** environment. If you're using an environment that has limited or no support for ES2015+ such as IE browsers then using [core-js](https://github.com/zloirock/core-js) will add polyfills for these methods._
 
+## API documentation
+
+<!-- START TOKEN(Autogenerated API docs|src/constants.js) -->
+
+Content within the HTML comment will be replaced by the generated documentation.
+
+<!-- END TOKEN(Autogenerated API docs|src/constants.js) -->`.
+
+<!-- START TOKEN(Autogenerated API docs|src/utils.js) -->
+
+Content within the HTML comment will be replaced by the generated documentation.
+
+<!-- END TOKEN(Autogenerated API docs|src/utils.js) -->`.
+
 <br/><br/><p align="center"><img src="https://s.w.org/style/images/codeispoetry.png?1" alt="Code is Poetry." /></p>