Add docs for ESLint plugin settings and rule options (#28059)

This PR adds documentation for the new `rootDir` setting (#27918), and for `next/no-html-link-for-pages`.

## Documentation / Examples

- [x] Make sure the linting passes

Author: mrmckeb

docs/basic-features/eslint.md

@@ -101,6 +101,25 @@ Next.js provides an ESLint plugin, [`eslint-plugin-next`](https://www.npmjs.com/
 
 If you already have ESLint configured in your application, we recommend extending from this plugin directly instead of including `eslint-config-next` unless a few conditions are met. Refer to the [Recommended Plugin Ruleset](/docs/basic-features/eslint.md#recommended-plugin-ruleset) to learn more.
 
+### Custom Settings
+
+#### `rootDir`
+
+If you're using `eslint-plugin-next` in a project where Next.js isn't installed in your root directory (such as a monorepo), you can tell `eslint-plugin-next` where to find your Next.js application using the `settings` property in your `.eslintrc`:
+
+```json
+{
+  "extends": "next",
+  "settings": {
+    "next": {
+      "rootDir": "/packages/my-app/"
+    }
+  }
+}
+```
+
+`rootDir` can be a path (relative or absolute), a glob (i.e. `"/packages/*/"`), or an array of paths and/or globs.
+
 ## Linting Custom Directories
 
 By default, Next.js will run ESLint for all files in the `pages/`, `components/`, and `lib/` directories. However, you can specify which directories using the `dirs` option in the `eslint` config in `next.config.js` for production builds:

errors/no-html-link-for-pages.md

@@ -40,6 +40,24 @@ function Home() {
 export default Home
 ```
 
+### Options
+
+#### `pagesDir`
+
+This rule can normally locate your `pages` directory automatically.
+
+If you're working in a monorepo, we recommend configuring the [`rootDir`](/docs/basic-features/eslint.md#rootDir) setting in `eslint-plugin-next`, which `pagesDir` will use to locate your `pages` directory.
+
+In some cases, you may also need to configure this rule directly by providing a `pages` directory. This can be a path or an array of paths.
+
+```json
+{
+  "rules": {
+    "@next/next/no-html-link-for-pages": ["error", "/my-app/pages/"]
+  }
+}
+```
+
 ### Useful Links
 
 - [next/link API Reference](https://nextjs.org/docs/api-reference/next/link)