[docs] update prettier installation instructions (#28681)

# Why

Following the current instructions in the docs aren't sufficient to set
up prettier in your project

# How

Add missing instructions.

# Test Plan

On a new SDK 51 project, run `npx expo lint` to create a an eslint
config and then follow the instructions in the docs to also set up
prettier.
Before: `npx expo lint` will not check for prettier errors
After: `npx expo lint` will check for prettier errors.

| Before      | After |
| ----------- | ----------- |
| <img width="971" alt="Screenshot 2024-05-08 at 14 19 40"
src="https://github.com/expo/expo/assets/6534400/7a8aa0f7-8c5e-4533-9c67-38e21785d433">
| <img width="958" alt="Screenshot 2024-05-08 at 14 20 49"
src="https://github.com/expo/expo/assets/6534400/97c1fbac-265b-469c-85fb-a3b005c8e305">
|

# Checklist

<!--
Please check the appropriate items below if they apply to your diff.
This is required for changes to Expo modules.
-->

- [ ] Documentation is up to date to reflect these changes (eg:
https://docs.expo.dev and README.md).
- [ ] Conforms with the [Documentation Writing Style
Guide](https://github.com/expo/expo/blob/main/guides/Expo%20Documentation%20Writing%20Style%20Guide.md)
- [ ] This diff will work correctly for `npx expo prebuild` & EAS Build
(eg: updated a module plugin).

docs/pages/guides/using-eslint.mdx

@@ -142,15 +142,31 @@ To install Prettier in your project:
 <Terminal
   cmd={[
     '# For other package managers',
-    '$ npx expo install -- --save-dev prettier',
+    '$ npx expo install -- --save-dev prettier eslint-config-prettier eslint-plugin-prettier',
     '',
     '# For yarn only',
-    '$ yarn add -D prettier',
+    '$ yarn add -D prettier eslint-config-prettier eslint-plugin-prettier',
   ]}
 />
 
 ### Setup
 
+To integrate Prettier with ESlint, update your **.eslintrc.js**:
+
+```js .eslintrc.js
+module.exports = {
+  extends: ["expo", "prettier"],
+  plugins: ["prettier"],
+  rules: {
+    "prettier/prettier": "error",
+  },
+};
+```
+
+Now, when you run `npx expo lint`, anything that is not aligned with Prettier formatting will be caught as an error.
+
+> **Note:** In the above configuration, you can use `"prettier/prettier": "warn"` if you prefer these formatting issues as warnings instead of errors.
+
 To customize Prettier settings, create a **.prettierrc** file at the root of your project and add your configuration.
 
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