fix: docs for dynamic routing in next 15 (#71531)

### What?

Fixes the `params` prop in
https://nextjs.org/docs/canary/app/building-your-application/routing/dynamic-routes

Also fixes a typo: `synchronoulsy` -> `synchronously`
### Why?

There is a breaking change in `next@15.0.0-rc.1`:
https://nextjs.org/blog/next-15-rc2#async-request-apis-breaking-change

Although the api docs have been updated, these have not been.

### How?

updates the docs. (relevant) build and lint passes locally. ran the
prettier fix.

---------

Co-authored-by: JJ Kasper <jj@jjsweb.site>

docs/02-app/01-building-your-application/01-routing/10-dynamic-routes.mdx

@@ -22,14 +22,20 @@ Dynamic Segments are passed as the `params` prop to [`layout`](/docs/app/api-ref
 For example, a blog could include the following route `app/blog/[slug]/page.js` where `[slug]` is the Dynamic Segment for blog posts.
 
 ```tsx filename="app/blog/[slug]/page.tsx" switcher
-export default function Page({ params }: { params: { slug: string } }) {
-  return <div>My Post: {params.slug}</div>
+export default async function Page({
+  params,
+}: {
+  params: Promise<{ slug: string }>
+}) {
+  const slug = (await params).slug
+  return <div>My Post: {slug}</div>
 }
 ```
 
 ```jsx filename="app/blog/[slug]/page.js" switcher
-export default function Page({ params }) {
-  return <div>My Post: {params.slug}</div>
+export default async function Page({ params }) {
+  const slug = (await params).slug
+  return <div>My Post: {slug}</div>
 }
 ```
 
@@ -41,7 +47,11 @@ export default function Page({ params }) {
 
 See the [generateStaticParams()](#generating-static-params) page to learn how to generate the params for the segment.
 
-> **Good to know**: Dynamic Segments are equivalent to [Dynamic Routes](/docs/pages/building-your-application/routing/dynamic-routes) in the `pages` directory.
+## Good to know
+
+- Since the `params` prop is a promise. You must use async/await or React's use function to access the values.
+  - In version 14 and earlier, `params` was a synchronous prop. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.
+- Dynamic Segments are equivalent to [Dynamic Routes](/docs/pages/building-your-application/routing/dynamic-routes) in the `pages` directory.
 
 ## Generating Static Params
 
@@ -105,13 +115,17 @@ The difference between **catch-all** and **optional catch-all** segments is that
 When using TypeScript, you can add types for `params` depending on your configured route segment.
 
 ```tsx filename="app/blog/[slug]/page.tsx" switcher
-export default function Page({ params }: { params: { slug: string } }) {
+export default async function Page({
+  params,
+}: {
+  params: Promise<{ slug: string }>
+}) {
   return <h1>My Page</h1>
 }
 ```
 
 ```jsx filename="app/blog/[slug]/page.js" switcher
-export default function Page({ params }) {
+export default async function Page({ params }) {
   return <h1>My Page</h1>
 }
 ```

docs/02-app/02-api-reference/02-file-conventions/default.mdx

@@ -55,4 +55,4 @@ export default async function Default({ params }) {
 | `app/[artist]/[album]/@sidebar/default.js` | `/zack/next` | `Promise<{ artist: 'zack', album: 'next' }>` |
 
 - Since the `params` prop is a promise. You must use `async/await` or React's [`use`](https://react.dev/reference/react/use) function to access the values.
-  - In version 14 and earlier, `params` was a synchronous prop. To help with backwards compatability, you can still access it synchronoulsy in Next.js 15, but this behavior will be deprecated in the future.
+  - In version 14 and earlier, `params` was a synchronous prop. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.

docs/02-app/02-api-reference/02-file-conventions/layout.mdx

@@ -82,7 +82,7 @@ export default async function Layout({ params }) {
 | `app/blog/[...slug]/layout.js`    | `/blog/1/2`    | `Promise<{ slug: ['1', '2'] }>`    |
 
 - Since the `params` prop is a promise. You must use `async/await` or React's [`use`](https://react.dev/reference/react/use) function to access the values.
-  - In version 14 and earlier, `params` was a synchronous prop. To help with backwards compatability, you can still access it synchronoulsy in Next.js 15, but this behavior will be deprecated in the future.
+  - In version 14 and earlier, `params` was a synchronous prop. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.
 
 ### Root Layouts
 

docs/02-app/02-api-reference/02-file-conventions/page.mdx

@@ -54,7 +54,7 @@ export default async function Page({ params }) {
 | `app/shop/[...slug]/page.js`         | `/shop/1/2` | `Promise<{ slug: ['1', '2'] }>`         |
 
 - Since the `params` prop is a promise. You must use `async/await` or React's [`use`](https://react.dev/reference/react/use) function to access the values.
-  - In version 14 and earlier, `params` was a synchronous prop. To help with backwards compatability, you can still access it synchronoulsy in Next.js 15, but this behavior will be deprecated in the future.
+  - In version 14 and earlier, `params` was a synchronous prop. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.
 
 #### `searchParams` (optional)
 
@@ -83,7 +83,7 @@ export default async function Page({ searchParams }) {
 | `/shop?a=1&a=2` | `Promise<{ a: ['1', '2'] }>`  |
 
 - Since the `searchParams` prop is a promise. You must use `async/await` or React's [`use`](https://react.dev/reference/react/use) function to access the values.
-  - In version 14 and earlier, `searchParams` was a synchronous prop. To help with backwards compatability, you can still access it synchronoulsy in Next.js 15, but this behavior will be deprecated in the future.
+  - In version 14 and earlier, `searchParams` was a synchronous prop. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.
 - `searchParams` is a **[Dynamic API](/docs/app/building-your-application/rendering/server-components#server-rendering-strategies#dynamic-apis)** whose values cannot be known ahead of time. Using it will opt the page into **[dynamic rendering](/docs/app/building-your-application/rendering/server-components#dynamic-rendering)** at request time.
 - `searchParams` is a plain JavaScript object, not a `URLSearchParams` instance.
 

docs/02-app/02-api-reference/04-functions/cookies.mdx

@@ -65,7 +65,7 @@ To learn more about these options, see the [MDN docs](https://developer.mozilla.
 ## Good to know
 
 - `cookies` is an **asynchronous** function that returns a promise. You must use `async/await` or React's [`use`](https://react.dev/reference/react/use) function to access cookies.
-  - In version 14 and earlier, `cookies` was a synchronous function. To help with backwards compatability, you can still access it synchronoulsy in Next.js 15, but this behavior will be deprecated in the future.
+  - In version 14 and earlier, `cookies` was a synchronous function. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.
 - `cookies` is a [Dynamic API](/docs/app/building-your-application/rendering/server-components#dynamic-apis) whose returned values cannot be known ahead of time. Using it in a layout or page will opt a route into [dynamic rendering](/docs/app/building-your-application/rendering/server-components#dynamic-rendering).
 - The `.delete` method can only be called:
   - In a [Server Action](/docs/app/building-your-application/data-fetching/server-actions-and-mutations) or [Route Handler](/docs/app/building-your-application/routing/route-handlers).

docs/02-app/02-api-reference/04-functions/draft-mode.mdx

@@ -39,7 +39,7 @@ The following methods and properties are available:
 ## Good to know
 
 - `draftMode` is an **asynchronous** function that returns a promise. You must use `async/await` or React's [`use`](https://react.dev/reference/react/use) function.
-  - In version 14 and earlier, `draftMode` was a synchronous function. To help with backwards compatability, you can still access it synchronoulsy in Next.js 15, but this behavior will be deprecated in the future.
+  - In version 14 and earlier, `draftMode` was a synchronous function. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.
 - A new bypass cookie value will be generated each time you run `next build`. This ensures that the bypass cookie can’t be guessed.
 - To test Draft Mode locally over HTTP, your browser will need to allow third-party cookies and local storage access.
 

docs/02-app/02-api-reference/04-functions/headers.mdx

@@ -43,7 +43,7 @@ export default async function Page() {
 ## Good to know
 
 - `headers` is an **asynchronous** function that returns a promise. You must use `async/await` or React's [`use`](https://react.dev/reference/react/use) function.
-  - In version 14 and earlier, `headers` was a synchronous function. To help with backwards compatability, you can still access it synchronoulsy in Next.js 15, but this behavior will be deprecated in the future.
+  - In version 14 and earlier, `headers` was a synchronous function. To help with backwards compatability, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.
 - Since `headers` is read-only, you cannot `set` or `delete` the outgoing request headers.
 - `headers` is a [Dynamic API](/docs/app/building-your-application/rendering/server-components#server-rendering-strategies#dynamic-apis) whose returned values cannot be known ahead of time. Using it in will opt a route into **[dynamic rendering](/docs/app/building-your-application/rendering/server-components#dynamic-rendering)**.