feat: add helix editor

[CSergienko]

Summary

Description:

• Tool repo URL: https://github.com/helix-editor/helix
• Plugin repo URL: https://github.com/CSergienko/asdf-helix

Checklist

• [ X ] Format with scripts/format.bash
• [ X ] Test locally with scripts/test_plugin.bash --file plugins/<your_new_plugin_name>
• [ X ] Your plugin CI tests are green
  • Tip: use the plugin_test action from asdf-actions in your plugin CI