Fix issue with options with multiple names

[Robert-96]

Hi, I found an issues with options that have multiple names. For example if the options has -n and --name in order to change the color of this options you will need to pass -n, to help_options_custom_colors.

@click.group(
    cls=HelpColorsGroup,
    help_headers_color='yellow',
    help_options_color='green',
    help_options_custom_colors={'-n,': 'red'}
)
def cli():
    pass

@cli.command()
@click.option('-n', '--name', help='The person to greet.')
def command(name):
    pass

The fix will allow -n, --name and -n, to work with help_options_custom_colors.

[r-m-n]

Thanks!