makeHelp function
Return a string that contains the usage and help information based on the arguments defined and the available builders.
Implementation
String makeHelp() {
final usage = argParser.usage;
return '''Usage: dcdg [options]
$usage
Available builders:
* ${availableBuilders().join('\n * ')}
The --$includeOption, --$excludeOption, --$hasAOption, and --$isAOption
options accept regular expressions. These options accept multiple values,
separated by commas, or they can be passed multiple times.
Note: If both $excludeOption and $includeOption are supplied, types that
are in both lists will be removed from the includes list and then the
includes list will be applied as usual.''';
}