fix: allow jsx/tsx with webpack

[wattanx]

🔗 Linked issue

Fixes: #17

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

jsx and tsx do not work when typescript: true is set.
I would like to add the isTSX option so that tsx and jsx will also work with webpack.
(I didn't write a test for tsx in nuxt2 because I thought there were few use cases using tsx.)

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.