fix: correct documentation for beforeNavigate

[Rich-Harris]

fixes #8597 and #8625

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[dummdidumm]

For ergonomic reasons (not creating another 1.x release and another merge in version-2 which will conflict blabla etc), should we just open this against version-2? I doubt many people will miss this documentation from the jsdoc hovering in practise, especially since it will be on the website anyway.
Change itself looks good 👍

[Rich-Harris]

i figure releases are free, no harm in squeezing in one more 1.x patch. shouldn't cause any merge conflicts