Fix color formatting logic in show_colors

[prjanitor]

The show_colors function had a hardcoded if true block which prevented the actual color hex string and padding logic from being executed. This PR replaces the hardcoded condition with a check on padding == 0 to allow both index-based display (when no padding is requested) and color-based display (when padding is provided), matching the intended behavior.

---

This PR was generated by PRJanitor — an automated tool that finds and fixes small bugs in open-source projects.

We respect your contribution guidelines — if your project doesn't accept bot PRs, we won't send more. You can also add a .github/prjanitor.yml file with enabled: false to opt out explicitly.