[Documentation] Use actual theme name

[sylhare]

📑 Summary

Remove the caps as it only works when all lowercase. (Base won't work, but base will)

📏 Design Decisions

Update documentation to reflect what's used. I thought that fixing the documentation was less error prone than changing the code.

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added unit/e2e tests (if appropriate)
• 🔖 targeted develop branch

[knsv]

This is how it should be! Thanks