feat: upgrade to typescript 6

[DylanPiercey]

• upgrade deps to typescript@6 (this means eg @marko/type-check now uses typescript@6).

resolves #470

[changeset-bot]

🦋 Changeset detected

Latest commit: db3cc48

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

This PR includes changesets to release 3 packages

Name	Type
@marko/language-server	Major
@marko/type-check	Major
marko-vscode	Major

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[coderabbitai]

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Walkthrough

A Changeset entry is added to record major version bumps for @marko/language-server, @marko/type-check, and marko-vscode packages. TypeScript is upgraded from ^5.9.3 to ^6.0.2 in the root package.json and in both the language-server and type-check package configurations. The @vscode/vsce dependency in the VS Code extension package is updated from ^3.7.1 to ^3.8.0.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'feat: upgrade to typescript 6' directly and clearly summarizes the main change in the pull request, which is upgrading the TypeScript dependency across multiple packages from version 5.9.3 to 6.0.2.
Description check	✅ Passed	The description accurately relates to the changeset, explaining that dependencies are upgraded to typescript@6 and that dependent packages like @marko/type-check will now use TypeScript 6, which aligns with the actual changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch typescript-6

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