Use custom print method for printing defaults.

Prints default arrays in a copy paste able way.

Difference in output:

Old:

    Options:
      [--ignore-files=one two three]
                                           # Default: ["**/spec/**/*.pp", "**/tests/**/*.pp", "**/example/**/*.pp"]
      [--disable-manifests=one two three]
                                           # Default: autoloader_layout

New:

    Options:
      [--ignore-files=one two three]
                                            # Default: "**/spec/**/*.pp" "**/tests/**/*.pp" "**/example/**/*.pp"
      [--disable-manifests=one two three]
                                           # Default: autoloader_layout
      [--verbose], [--no-verbose]