Update fgpyo/util/metric.py

Co-authored-by: Clint Valentine <[email protected]>

Author: TedBrookings

fgpyo/util/metric.py

@@ -11,7 +11,7 @@
 The :class:`~fgpyo.util.metric.Metric` class makes it easy to read, write, and store one or metrics
 of the same type, all the while preserving types for each value in a metric.  It is an abstract
 base class decorated by `@dataclass <https://docs.python.org/3/library/dataclasses.html>`_, or
-`attr <https://www.attrs.org/en/stable/examples.html>`_, with attributes storing one or more typed
+`@attr.s <https://www.attrs.org/en/stable/examples.html>`_, with attributes storing one or more typed
 values.
 
 Examples