bpo-35892: Add usage note to mode() (GH-15122)

Doc/library/statistics.rst

@@ -313,7 +313,9 @@ However, for reading convenience, most of the examples show sorted sequences.
    measure of central location.
 
    If there are multiple modes, returns the first one encountered in the *data*.
-   If *data* is empty, :exc:`StatisticsError` is raised.
+   If the smallest or largest of multiple modes is desired instead, use
+   ``min(multimode(data))`` or ``max(multimode(data))``.  If the input *data* is
+   empty, :exc:`StatisticsError` is raised.
 
    ``mode`` assumes discrete data, and returns a single value. This is the
    standard treatment of the mode as commonly taught in schools: