updated todo html

[Harsh3363]

🛠️ Fixes Issue #790

👨‍💻 Changes proposed

I have added required in the HTML file which will make entry in the input field mandatory

✅ Check List (Check all the applicable boxes)

• [x] My code doesn't break any part of the project (Zero Octave-Javascript-Projects).
• [x] This PR does not contain plagiarized content.
• [x] My Addition/Changes works properly and matches the overall repo pattern.
• [x] The title of my pull request is a short description of the requested changes.

📄 Note to reviewers

📷 Screenshots