fix: use inline element in heading

[devCrossNet]

Just created my first project with svelte kit and came across this minor issue. div is not allowed as a child for heading, changed it to span.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 565002c

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

This PR includes changesets to release 1 package

Name	Type
create-svelte	Patch

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[Rich-Harris]

thank you!