Implement description on hover

[schickling]

GraphiQL has introduced a couple of useful improvements over the last few months which should be merged back into the GraphQL Playground such as clicking on a field and opening it in the docs sidenav or tooltip descriptions when hovering a field in the query editor.

See GraphiQL releases for other features.

[timsuchanek]

The "click on field" has been implemented recently by @HuVik, the hover is still missing.

[huv1k]

I will add it to dynamic styles PR

[timsuchanek]

Awesome!

[huv1k]

Hover is working in the new version it just needs some design adjustments