docs: move fake timer timeout explanation from core to user-event

Author: domnantas

docs/guides-using-fake-timers.mdx

@@ -13,11 +13,6 @@ code, most testing frameworks offer the option to replace the real timers in
 your tests with fake ones. This has a side effect - when using fake timers in
 your tests, _all_ of the code inside your test uses fake timers.
 
-This becomes apparent when using [`user-event`](user-event/intro.mdx) to test
-user interactions. Internally, it uses `setTimeout` to
-[`delay`](user-event/options.mdx#delay) subsequent actions and allow
-asynchronous code to run between the inputs.
-
 The common pattern to setup fake timers is usually within the `beforeEach`, for
 example:
 
@@ -52,21 +47,10 @@ afterEach(() => {
 })
 ```
 
-## Using fake timers together with `user-event`
-
-`user-event` internally uses `setTimeout` to delay subsequent actions. Using
-fake timers in such tests will cause timeouts, since the `setTimeout` callbacks
-do not get executed. In order to allow `user-event` to advance the fake timers,
-it is necessary to set [`advanceTimers`](user-event/options.mdx#advancetimers)
-option in `userEvent.setup()`:
-
-```js
-const user = userEvent.setup({advanceTimers: jest.advanceTimersByTime})
-```
-
-:::caution
+:::note
 
-You may find suggestions to set `delay: null` in `userEvent.setup()` in order to
-solve this issue. That is not recommended, as it may cause unexpected behaviour.
+Combining fake timers with `user-event` may cause test timeouts. Refer to
+[`advanceTimers`](user-event/options.mdx#advancetimers) option to prevent this
+issue.
 
 :::

docs/user-event/options.mdx

@@ -8,8 +8,19 @@ can be applied per [`setup()`](setup.mdx).
 
 ### advanceTimers
 
-If you are using fake timers, you need to advance your timers when we internally
-[delay](#delay) subsequent code.
+`user-event` adds a [delay](#delay) between some subsequent inputs. When using
+[fake timers](/guides-using-fake-timers.mdx) it is necessary to set this option
+to your test runner's time advancement function. For example,
+`jest.advanceTimersByTime`, `vi.advanceTimersByTime`, or `mock.timers.tick` for
+`node:test`.
+
+:::caution
+
+You may find suggestions to set `delay: null` to prevent test timeouts when
+using fake timers. That is not recommended, as it may cause unexpected
+behaviour. Starting from v14.1, we suggest using `advanceTimers` option instead.
+
+:::
 
 ```ts
 (delay: number) => Promise<void> | void