Describe your problem and - if possible - how to reproduce it

In the JS course, the Debugging - Understanding the Differences between the freeCodeCamp and Browser Console lesson doesn't properly evaluate on Firefox, showing invalid regexp group in the bottom console. On Chrome, however, it works just fine. The issue has to do with the regexp used to check console.clear().

Add a Link to the page with the problem

https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/debugging/understanding-the-differences-between-the-freecodecamp-and-browser-console

Tell us about your browser and operating system

• Browser Name: Firefox
• Browser Version: Developer Edition / 61.0b10 (64-bit)
• Operating System: Windows 10

If possible, add a screenshot here