Docs: Formatting for code blocks nested in blockquote

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
Styling in docs

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem. Your bug will get fixed much faster if we can run your code and it doesn't have dependencies other than React. Paste the link to your JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new) example below:

As seen https://reactjs.org/docs/hooks-reference.html#usestate

What is the expected behavior?

Code blocks nested in block quotes should not have negative margin space.

Missing:

blockquote .gatsby-highlight {
  margin-left: 0px;
}

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?

Start at the Hooks reference page linked in the issue and inspect the documentation styles affecting .gatsby-highlight inside blockquotes. Confirm the nested code block no longer has negative margin space and compare the rendered result with the supplied screenshots.