docs: update hooks docs (again)

[Rich-Harris]

so confused about how these changes got missed from #16417

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from ffdcb5a:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/ffdcb5ac05159f3f6974615d0f1481dfe4416ef4

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16420

[changeset-bot]

⚠️ No Changeset found

Latest commit: ffdcb5a

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