Remove unused import and use correct file extension

[Dr-Electron]

Description of change

As discussed here, I removed the unused imports and changed the file extension. Wondering if there is a linter for unused imports 🤔

Change checklist

• [x] I have followed the contribution guidelines for this project
• [x] I have performed a self-review of my own changes
• [x] I have made sure that added/changed links still work
• [x] I have commented my code, particularly in hard-to-understand areas