chore: fix typos

[Fdawgs]

Checklist

• Run npm test
• Documentation has been updated and adheres to the style described in CONTRIBUTING.md
• Commit message adheres to the Conventional commits style, following the @commitlint/config-conventional config

[Copilot]

Pull request overview

This PR performs small typo/formatting corrections in documentation and JSDoc, improving consistency of naming and generated docs without changing runtime behavior.

Changes:

• Fixes JSDoc @returns spacing/formatting in UnRTF#convert.
• Fixes a README example typo to use the correct unRtf instance name.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated no comments.

File	Description
src/index.js	JSDoc formatting cleanup for the convert method return annotation.
README.md	Corrects the promise-chaining example to call .convert on unRtf (matching the variable declaration).

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.