Add path to Image documentation (#82329)

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### How?

Closes NEXT-
Fixes #

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### What?

Add the `path` field to the App Router
https://nextjs.org/docs/app/api-reference/components/image and Pages
Router https://nextjs.org/docs/pages/api-reference/components/image
docs. This field is valid for both, and currently it's use is hidden in
the code.

### Why?

Allow people to find and use the field as it is useful for prefixing the
`/_next/image` path.

---------

Co-authored-by: Steven <[email protected]>

docs/01-app/03-api-reference/02-components/image.mdx

@@ -636,6 +636,18 @@ export default function myImageLoader({ src, width, quality }) {
 
 > Alternatively, you can use the [`loader` prop](#loader) to configure each instance of `next/image`.
 
+#### `path`
+
+If you want to change or prefix the default path for the Image Optimization API, you can do so with the `path` property. The default value for `path` is `/_next/image`.
+
+```js filename="next.config.js"
+module.exports = {
+  images: {
+    path: '/my-prefix/_next/image',
+  },
+}
+```
+
 #### `deviceSizes`
 
 `deviceSizes` allows you to specify a list of device width breakpoints. These widths are used when the `next/image` component uses [`sizes`](#sizes) prop to ensure the correct image is served for the user's device.

docs/02-pages/04-api-reference/01-components/image-legacy.mdx

@@ -441,6 +441,18 @@ module.exports = {
 }
 ```
 
+#### Customizing the Built-in Image Path
+
+If you want to change or prefix the default path for the built-in Next.js image optimization, you can do so with the `path` property. The default value for `path` is `/_next/image`.
+
+```js filename="next.config.js"
+module.exports = {
+  images: {
+    path: '/my-prefix/_next/image',
+  },
+}
+```
+
 ### Built-in Loaders
 
 The following Image Optimization cloud providers are included:

packages/next/src/shared/lib/image-config.ts

@@ -83,7 +83,7 @@ export type ImageConfigComplete = {
   /** @see [Image loaders configuration](https://nextjs.org/docs/api-reference/next/legacy/image#loader) */
   loader: LoaderValue
 
-  /** @see [Image loader configuration](https://nextjs.org/docs/api-reference/next/legacy/image#loader-configuration) */
+  /** @see [Image loader configuration](https://nextjs.org/docs/app/api-reference/components/image#path) */
   path: string
 
   /** @see [Image loader configuration](https://nextjs.org/docs/api-reference/next/image#loader-configuration) */