Small CLI cleanups

* yapf changes
* Fix the cformat test
* Make the normpath test work when run from /
* `qmk config`: Mark `--read-only` as arg_only

lib/python/qmk/cli/config.py

@@ -12,7 +12,7 @@ def print_config(section, key):
     cli.echo('%s.%s{fg_cyan}={fg_reset}%s', section, key, cli.config[section][key])
 
 
-@cli.argument('-ro', '--read-only', action='store_true', help='Operate in read-only mode.')
+@cli.argument('-ro', '--read-only', arg_only=True, action='store_true', help='Operate in read-only mode.')
 @cli.argument('configs', nargs='*', arg_only=True, help='Configuration options to read or write.')
 @cli.subcommand("Read and write configuration settings.")
 def config(cli):