docs: fix $effect section examples

[navorite]

It seems #12200 is back again after the site migration, maybe it is worth checking if previous docs fixes exist or not.

closes #13912

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Latest commit: 944f9bb

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[pkg-pr-new]

pnpm add https://pkg.pr.new/svelte@13911

commit: 944f9bb

[rintheo]

This also fixes #13912 .

[navorite]

This also fixes #13912 .

Oh, thanks for noting this. I think the old preview site docs were used in the current site, that's why some of the docs fixes applied to the preview site are not applied to the current site.

[dummdidumm]

thank you!