docs: improve cancellation docs (#2932)

docs/src/pages/guides/query-cancellation.md

@@ -5,12 +5,18 @@ title: Query Cancellation
 
 [_Previous method requiring a `cancel` function_](#old-cancel-function)
 
-React Query provides each query function with an [`AbortSignal` instance](https://developer.mozilla.org/docs/Web/API/AbortSignal) **if it's available in your runtime environment**. When a query becomes out-of-date or inactive, this `signal` will become aborted. This means that all queries are cancellable and you can respond to the cancellation inside your query function if desired. The best part about this is that it allow you to continue to use normal async/await syntax while getting all the benefits of automatic cancellation. Additionally, this solution works better with TypeScript than the old solution.
+React Query provides each query function with an [`AbortSignal` instance](https://developer.mozilla.org/docs/Web/API/AbortSignal), **if it's available in your runtime environment**. When a query becomes out-of-date or inactive, this `signal` will become aborted. This means that all queries are cancellable, and you can respond to the cancellation inside your query function if desired. The best part about this is that it allows you to continue to use normal async/await syntax while getting all the benefits of automatic cancellation. Additionally, this solution works better with TypeScript than the old solution.
 
 The `AbortController` API is available in [most runtime environments](https://developer.mozilla.org/docs/Web/API/AbortController#browser_compatibility), but if the runtime environment does not support it then the query function will receive `undefined` in its place. You may choose to polyfill the `AbortController` API if you wish, there are [several available](https://www.npmjs.com/search?q=abortcontroller%20polyfill).
 
 **NOTE:** This feature was introduced at version `3.30.0`. If you are using an older version, you will need to either upgrade (recommended) or use the [old `cancel` function](#old-cancel-function).
 
+## Default behavior
+
+By default, queries that unmount or become unused before their promises are resolved are _not_ cancelled. This means that after the promise has resolved, the resulting data will be available in the cache. This is helpful if you've started receiving a query, but then unmount the component before it finishes. If you mount the component again and the query has not been garbage collected yet, data will be available.
+
+However, if you consume the `AbortSignal` or attach a `cancel` function to your Promise, the Promise will be cancelled (e.g. aborting the fetch) and therefore, also the Query must be cancelled. Cancelling the query will result in its state being _reverted_ to its previous state.
+
 ## Using `fetch`
 
 ```js
@@ -93,7 +99,7 @@ const query = useQuery('todos', ({ signal }) => {
 
 ## Manual Cancellation
 
-You might want to cancel a query manually. For example, if the request takes a long time to finish, you can allow the user to click a cancel button to stop the request. To do this, you just need to call `queryClient.cancelQueries(key)`. If `promise.cancel` is available or you have consumed the `signal` passed to the query function then React Query will cancel the request.
+You might want to cancel a query manually. For example, if the request takes a long time to finish, you can allow the user to click a cancel button to stop the request. To do this, you just need to call `queryClient.cancelQueries(key)`, which will cancel the query and revert it back to its previous state. If `promise.cancel` is available, or you have consumed the `signal` passed to the query function, React Query will additionally also cancel the Promise.
 
 ```js
 const [queryKey] = useState('todos')