Remove unnecessary `object` base class in docs (#10366).
Also add a note about inheritance from `object` being default.
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index f66b0c9..f612a1c 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -322,7 +322,7 @@
:func:`groupby` is equivalent to::
- class groupby(object):
+ class groupby:
# [k for k, g in groupby('AAAABBBCCDAABBB')] --> A B C D A B
# [list(g) for k, g in groupby('AAAABBBCCD')] --> AAAA BBB CC D
def __init__(self, iterable, key=None):