chore: fix jsdoc errors and add some examples, pt. 1.

[igalklebanov]

Hey 👋

This PR fixes some erroneous JSDocs, and also adds some examples.

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Name	Status	Preview	Comments	Updated (UTC)
kysely	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Nov 19, 2024 7:44am

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Open in Stackblitz • kysely_koa_example

npm i https://pkg.pr.new/kysely-org/kysely@1264

commit: d93a972