Use DevTools updates

Hey @PaulKinlan I have a question on this. Support with variables in those `note` sort of lists seem to be a bit funny which makes using `{{site.fundamentals}}` trickier. Previously, the domain was hardcoded as `web-central.appspot.com`, I have removed the domain portion and left it as a relative URL. Is that ok? If not I can undo it.

Other changes:
* Avoid an extra redirection in DevTools doc link.
* Spelling correction.