feat: ignore *.{test,spec}.{js,ts} and similar files

[rChaoz]

Closes #13008, please see issue for more details

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[changeset-bot]

🦋 Changeset detected

Latest commit: 6c43108

The changes in this PR will be included in the next version bump.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 6e0f0eb

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Minor

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Click here if you're a maintainer who wants to add another changeset to this PR

[Rich-Harris]

preview: https://svelte-dev-git-preview-kit-13009-svelte.vercel.app/

this is an automated message