fix: update state_referenced_locally message

[Rich-Harris]

alternative to #15171. closes #11883, closes #13079.

In addition to tweaking the message (and suggesting a derived instead of a closure when the reference is inside a $state declaration, per #15171 (comment)) it tweaks the detailed description the message links to.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 8eb15c3

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

This PR includes changesets to release 1 package

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svelte	Patch

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[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-svelte-15733-svelte.vercel.app/

[github-actions]

Playground

pnpm add https://pkg.pr.new/svelte@15733

[Rich-Harris]

merged per discussion in #15171