Update tailwind docs to ensure users install the tailwind cli

[BinaryShrub]

See https://github.com/schultek/jaspr/issues/242

Description

Type of Change

Ready Checklist

• [ ] I've read the Contribution Guide.
• [ ] In case this PR changes one of the core packages, I've modified the respective CHANGELOG.md file using the semantic_changelog format.
• [ ] I updated/added relevant documentation (doc comments with ///).
• [ ] I added myself to the AUTHORS file (optional, if you want to).