fix: add colon

[RitaDee]

Description

Added colon for language list in the course introduction.

What type of PR is this? (check all applicable)

• [ ] 🍕 Feature
• [ ] 🐛 Bug Fix
• [x] 📝 Documentation Update
• [ ] 🎨 Style
• [ ] 🧑‍💻 Code Refactor
• [ ] 🔥 Performance Improvements
• [ ] ✅ Test
• [ ] 🤖 Build
• [ ] 🔁 CI
• [ ] 📦 Chore (Release)
• [ ] ⏩ Revert

Related Tickets & Documents

Fixes #52

Mobile & Desktop Screenshots/Recordings

Added tests?

• [ ] 👍 yes
• [x] 🙅 no, because they aren't needed
• [ ] 🙋 no, because I need help

Added to documentation?

• [ ] 📜 README.md
• [x] 📓 docs.opensauced.pizza
• [ ] 🍕 dev.to/opensauced
• [ ] 📕 storybook
• [ ] 🙅 no documentation needed

[optional] Are there any post-deployment tasks we need to perform?

[optional] What gif best describes this PR or how it makes you feel?

[netlify[bot]]

✅ Deploy Preview for sauced-intro ready!

Name	Link
🔨 Latest commit	eee4299d3101fb9bfbd6ceee467ea8438e663180
🔍 Latest deploy log	https://app.netlify.com/sites/sauced-intro/deploys/6511e02a18594f0008902287
😎 Deploy Preview	https://deploy-preview-54--sauced-intro.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.