Add rich handler to debug logging

[wren]

This PR adds small, quality-of-life improvements to the debug logging. As we add more logging, this will see even more benefit. See below for before and after screenshots.

Before:

After:

Checklist

• I have read the contributing doc.
• I have included a link to the relevant issue number.
• I have checked to ensure there aren't other open pull requests
  for the same issue.
• I have written new tests for these changes, as needed.

[micahellison]

Wow, it's so much more readable! Looks good on Windows too.

[alichtman]

Thanks @wren! Way easier to read the debug log now.