fix doc

Author: thomwolf

src/nlp/metric.py

@@ -125,6 +125,7 @@ def format(self) -> Optional[str]:
 
 class Metric(MetricInfoMixin):
     """A Metrics is the base class and common API for all metrics.
+
     Args:
         config_name (``str``): This is used to define a hash specific to a metrics computation script and prevents the metric's data
             to be overridden when the metric loading script is modified.