fix declaration of StatisticsError
diff --git a/Doc/library/statistics.rst b/Doc/library/statistics.rst
index f3eca8c..fc99d81 100644
--- a/Doc/library/statistics.rst
+++ b/Doc/library/statistics.rst
@@ -454,9 +454,9 @@
A single exception is defined:
-:exc:`StatisticsError`
+.. exception:: `StatisticsError`
-Subclass of :exc:`ValueError` for statistics-related exceptions.
+ Subclass of :exc:`ValueError` for statistics-related exceptions.
..
# This modelines must appear within the last ten lines of the file.