Add Error Handling document

[amandeepmittal]

This PR adds a new Error Handling section and addresses questions around the React Error Boundaries and error pages in a Next.js app from the issue: https://github.com/vercel/documentation/issues/106

Bug

• Related issues linked using fixes #number
• Integration tests added
• Errors have helpful link attached, see contributing.md

Feature

• Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
• Related issues linked using fixes #number
• Integration tests added
• Documentation added
• Telemetry added. In case of a feature if it's used or not.
• Errors have helpful link attached, see contributing.md

Documentation / Examples

• Make sure the linting passes by running yarn lint

[amandeepmittal]

@styfle, I've updated the doc as per your suggestions and commits. Please have a look 🙏

I'm also moving this PR from Draft to PR mode

[raphaelsaunier]

I was about to open an issue about using react-error-boundary with Next.js before stumbling upon this PR; hope you won't mind me chiming in. If you believe this should rather be treated in its own separate issue, let me know! 😃

As reported here bvaughn/react-error-boundary#100 by someone else, the Next.js error overlay takes precedence and always shows up even when an error is thrown. I just tried with your proposed ErrorBoundary class component and it behaves in the exact same way; the fallback UI/component is displayed but the error also shows up in the error overlay in development and causes the build to fail when running next build.

In my case I'm rendering content that comes from a dynamic source (headless CMS) and I'd like to add some extra safety if some of the data is missing or incomplete. Error boundaries would've allowed me to handle this in an elegant way.

[styfle]

Thanks!