[Docs] add note to clarify use of Link when clearing preview cookies …

…(issue #34129) (#34142)

Add note that explains the need to pass `prefetch={false}` to `Link` component to prevent clearing cookies accidentally
(responding to issue "Docs: potential preview-mode error on production build #34129").

Note as follows:

> **Note:** If calling this route using `Link` component, you must pass in `prefetch={false}` to prevent calling `clearPreviewData` during prefetch.



## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ x] Make sure the linting passes by running `yarn lint`

docs/advanced-features/preview-mode.md

@@ -186,6 +186,8 @@ export default function handler(req, res) {
 }
 ```
 
+> **Note:** If calling this route using `Link` component, you must pass in `prefetch={false}` to prevent calling `clearPreviewData` during prefetch.
+
 ### Specify the preview mode duration
 
 `setPreviewData` takes an optional second parameter which should be an options object. It accepts the following keys: