Support pages/_document as a function component

[timneutkens]

Feature request

Is your feature request related to a problem? Please describe.

Converting _document to a function component has no real benefits currently besides being able to use useContext but there's no context wrapper above _document that you can use with useContext. useState, useEffect, and other hooks will not work as well given that _document is not hydrated client-side.

Even though there are no benefits the question to support a function instead of a class comes up from time to time in #7515, hence why I'm creating this story.

Describe the solution you'd like

_document is currently not a function component for backwards compat reasons, we can likely take a similar approach to what we did for _app though by having getInitialProps fall back to the default value.

[hasanzahran]

Is there any update regarding this issue.

Thanks