Writes the help text to the formatter if it exists.

def format_help_text(self, ctx, formatter):
        """Writes the help text to the formatter if it exists."""
        if self.help:
            formatter.write_paragraph()
            with formatter.indentation():
                help_text = self.help
                if self.deprecated:
                    help_text += DEPRECATED_HELP_NOTICE
                formatter.write_text(help_text)
        elif self.deprecated:
            formatter.write_paragraph()
            with formatter.indentation():
                formatter.write_text(DEPRECATED_HELP_NOTICE)