`console.warn` when html-jsx-lib.js is loaded

_js/html-jsx-lib.js

@@ -1 +1,7 @@
-// This file has moved to http://reactjs.github.io/react-magic/htmltojsx.min.js
+// Ideally it would be nice to just redirect, but Github Pages is very basic and
+// lacks that functionality.
+console.warn(
+  'html-jsx-lib.js has moved to http://reactjs.github.io/react-magic/' +
+  'htmltojsx.min.js. If using React-Magic, you are no longer required to ' +
+  'link to this file. Please delete its <script> tag.'
+);