[VarDumper] Improved dump in html

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | http://www.w3.org/TR/html5/dom.html#the-id-attribute
| License       | MIT
| Doc PR        | -


Oh I didn't see that, it's a cool feature!
Though, I had a similar idea, but maybe a little bit better: instead of opening the target of the link, we could just swap the childs of the object and toggle the structure right where it is clicked on. That would make navigation even smoother.
If you're ok, I propose you revert this feature and keep this PR purelly on the id subject, then we can work on an other one with this ref displaying feature.