This comes up a lot in discussions/as an issue, so added a small comment about uploading files to the public directory. I'm not sure if it is worth a deeper technical explanation as well.

currently, the `no-html-link-for-pages` eslint rule will look for the pages folder in either `pages`, or a custom folder provided via rule option. this PR adds support for also looking in `src/pages` by default.

(sidenote: not sure about the custom pagesfolder path: does next support locations other than `pages` and `src/pages`)?)

fixes  #16426

fix #16752

cc @thuringia

Including prettier changes that were done automatically after the code sample became valid.

This makes sure we have the correct `asPath` value to prevent breaking hydration for `getServerSideProps` pages and doesn't re-use the `resolvedUrl` value for the `asPath` and instead creates a separate `resolvedAsPath` value that only removes the `_next/data` prefix from the path. Additional tests have been added in the `getServerSideProps` suite to ensure correct `asPath` with rewrites. 

Fixes: https://github.com/vercel/next.js/issues/17113

On the latest beta of webpack 5 resolving fails with the below error and according to https://github.com/webpack/webpack/issues/11467 is due to the imports in this module not being fully specified. This adds the config mentioned in the thread to correct the resolving for this module. 

```sh
Failed to compile.
--
16:33:50.046 | ModuleNotFoundError: Module not found: Error: Can't resolve './assertThisInitialized' in '/vercel/f03cc85/node_modules/@babel/runtime/helpers/esm'
16:33:50.046 | > Build error occurred
16:33:50.047 | Error: > Build failed because of webpack errors
16:33:50.047 | at build (/vercel/f03cc85/node_modules/next/dist/build/index.js:15:918)
16:33:50.099 | error Command failed with exit code 1.
```
 

Fixes SSG pages that start with `/api` not being detected as SSG pages. This also adds tests to ensure this is working correctly in the `prerender` suite.

x-ref: https://github.com/vercel/next.js/issues/17091 

This continues off of https://github.com/vercel/next.js/pull/17081 and provides this normalized `asPath` value in the context provided to `getServerSideProps` to provide the consistent value since the request URL can vary between direct visit and client transition and the alternative requires building the URL each time manually. 

Kept this change separate from https://github.com/vercel/next.js/pull/17081 since this is addressing a separate issue and allows discussion separately. 

Closes: https://github.com/vercel/next.js/issues/16407

This normalizes the `asPath` for `getServerSideProps` and `getStaticProps` pages to ensure it matches the value that would show on the client instead of a) the output pathname when revalidating or generating a fallback or b) the `_next/data` URL on client transition. 

Fixes: https://github.com/vercel/next.js/issues/16542

Earlier today #17038 was merged which I opened to fix a problem when using `webpack@5.0.0-beta.30` with Next.js using the new Webpack 5 support. In that PR, the only change was the renaming of a configuration key. I later discovered that the change on the Webpack side was different than I initially thought, and this meant that the fix I submittted to Next.js didn't work.

This PR intends to fix the remaining problems. Webpack 5 now accepts a `environment` key that can be used to configure the target output. Previously, this was known as `ecmaVersion` and accepted a number. Now, `environment` accepts a configuration object with individual options. I've configured this in such a way where it resembles an ES5 environment:
```js
environment: {
   arrowFunction: false,
   bigIntLiteral: false,
   const: false,
   destructuring: false,
   dynamicImport: false,
   forOf: false,
   module: false,
}
```

This uses the "Expand directories" feature introduces in Prettier 2.0 to automatically format all supported file types.

Also, I fixed some badly formatted files.

For some reason babel-plugin-syntax-jsx of babel 6 was used instead of
babel 7 version.

Throughout some of the blog examples word `formatter` is spelled as `formater`, this PR changes all of them to `formatter`

This PR fixes #17035. As described in the issue, there was a breaking change in `webpack@5.0.0-beta.30`: `output.ecmaVersion` was replaced by `output.environment`. This meant Next.js apps using this `webpack` version would break. This PR updates the relevant Webpack config.

I think this will break any apps that are still using `webpack@5.0.0-beta.29`, but I don't know whether that is a problem as this is a beta feature. If it is, I'd love it if someone could let me know how to detect beta versions in the code so I can make it backwards-compatible.

Co-authored-by: NJoe Haddad <joe.haddad@zeit.co>

Since [the current link](https://nextjs.org/docs/api-reference/next.config.js/environment-variables) for the build-time environment variables docs recommends the approach outlined in [this section](https://nextjs.org/docs/basic-features/environment-variables), I think the link should point there instead.

ref https://github.com/GoogleChrome/web-vitals/pull/68

won't fail the new [`no-unload-listeners`](https://github.com/GoogleChrome/lighthouse/pull/11085) Lighthouse audit.

Ref https://github.com/webpack-contrib/terser-webpack-plugin/blob/v4.1.0/package.json#L44

cacache is a dependency of terser-webpack-plugin. The latest version
depends on cacache 15 while next adds cacache 13. This may give
unexpected results. Better keep it in sync with terser plugin.

Babel-preset-env includes includes optional chaining and
nullish-coalescing since [7.8.0](https://github.com/babel/babel/releases/tag/v7.8.0).

In this diff I removed these plugins from next preset to prevent
dependency duplication when their newer versions are out.

The new version replaced big clone-deep package with dependency-free klona
- https://github.com/webpack-contrib/sass-loader/releases/tag/v10.0.0
- https://github.com/webpack-contrib/sass-loader/releases/tag/v9.0.0

Also deduped some related transitives.

There was a security update for node-fetch.

> This is an important security release. It is strongly recommended to update as soon as possible.
https://github.com/node-fetch/node-fetch/blob/master/docs/CHANGELOG.md#v261

Closes: https://github.com/vercel/next.js/issues/14433

Co-authored-by: NJoe Haddad <joe.haddad@zeit.co>