Command line arguments for configuration files

- Is it `configfile` or `configfiles` ? 
- pattern `--config` of Markdown seems to be ``--config`` in RST (I will double check that with my previous commit)
- [API](https://snakemake.readthedocs.io/en/latest/api_reference/snakemake.html#api-reference-snakemake) references`configfiles`, but does not describe CLI parameter

docs/snakefiles/configuration.rst

@@ -39,7 +39,7 @@ In addition to the `configfile` statement, config values can be overwritten via
 Further, you can manually alter the config dictionary using any Python code **outside** of your rules. Changes made from within a rule won't be seen from other rules.
 Finally, you can use the `--configfile` command line argument to overwrite values from the `configfile` statement.
 Note that any values parsed into the `config` dictionary with any of above mechanisms are merged, i.e., all keys defined via a `configfile`
-statement, or the `--configfile` and `--config` command line arguments will end up in the final `config` dictionary, but if two methods define the same key, command line
+statement, or the ``--configfiles`` and ``--config`` command line arguments will end up in the final `config` dictionary, but if two methods define the same key, command line
 overwrites the `configfile` statement.
 
 For adding config placeholders into a shell command, Python string formatting syntax requires you to leave out the quotes around the key name, like so: