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?

从 issue 中链接的 Hooks 参考页面开始，检查影响 blockquotes 内 .gatsby-highlight 的文档样式。确认嵌套代码块不再有负边距空间，并将渲染结果与提供的屏幕截图进行比较。