docs: improve data fetching docs (#21197)

docs/1.getting-started/6.data-fetching.md

@@ -21,7 +21,7 @@ When using a framework like Nuxt that can perform calls and render pages on both
 
 ### Network calls duplication
 
-The `useFetch` and `useAsyncData` composables ensure that once an API call is made on the server, the data is properly forwarded to the client in the payload. This JavaScript object is accessible through `window.__NUXT__` and is used on the client to avoid refetching the same data when the code is executed in the browser.
+The `useFetch` and `useAsyncData` composables ensure that once an API call is made on the server, the data is properly forwarded to the client in the payload. This JavaScript object is accessible through [`useNuxtApp().payload`](/docs/api/composables/use-nuxt-app#payload) and is used on the client to avoid refetching the same data when the code is executed in the browser.
 
 ::alert{icon=⚙️}
 Use the [Nuxt DevTools](https://devtools.nuxtjs.org) to inspect this data in the payload tab.
@@ -186,18 +186,22 @@ const { data: mountains } = await useFetch('/api/mountains', {
 
 #### Keys
 
-`useFetch` and `useAsyncData` use keys to prevent refetching the same data (for example when navigating back to a page previously rendered).
+`useFetch` and `useAsyncData` use keys to prevent refetching the same data.
 
 - `useFetch` uses the provided URL as a key. Alternatively, a `key` value can be provided in the `options` object passed as a last argument.
 - `useAsyncData` uses its first argument as a key if it is a string. If the first argument is the handler function that performs the query, then a key that is unique to the file name and line number of the instance of `useAsyncData` will be generated for you.
 
-#### Refresh
+::alert{icon=📘}
+To get the cached data by key, you can use [`useNuxtData`](/docs/api/composables/use-nuxt-data)
+::
+
+#### Refresh and execute
 
-If you want to force the function to re-run, you can manually change the key or use the `refresh` function provided by the composables.
+If you want to fetch or refresh data manually, use the `execute` or `refresh` function provided by the composables. (`execute` is an alias for `refresh` that works in exactly the same way but is more semantic for cases when `immediate: false`).
 
 ```vue
 <script setup>
-const { data, error, refresh } = await useFetch('/api/users')
+const { data, error, execute, refresh } = await useFetch('/api/users')
 </script>
 
 <template>