docs: Update devtools.md (#5950)

installing it as a regular dependency doesn't work during development with next 13 app dir. Import trace errors thrown all around.

docs/react/devtools.md

@@ -22,6 +22,7 @@ $ pnpm add @tanstack/react-query-devtools
 # or
 $ yarn add @tanstack/react-query-devtools
 ```
+For Next 13+ App Dir you must install it as a dev dependency for it to work.
 
 You can import the devtools like this:
 
@@ -31,6 +32,7 @@ import { ReactQueryDevtools } from '@tanstack/react-query-devtools'
 
 By default, React Query Devtools are only included in bundles when `process.env.NODE_ENV === 'development'`, so you don't need to worry about excluding them during a production build.
 
+
 ## Floating Mode
 
 Floating Mode will mount the devtools as a fixed, floating element in your app and provide a toggle in the corner of the screen to show and hide the devtools. This toggle state will be stored and remembered in localStorage across reloads.