Fix typo in unittest.mock documentation: manger -> manager (GH-12352)


(cherry picked from commit dc69f69f14fb89511d018a3927fc6378a58d2def)

Co-authored-by: Joan Massich <mailsik@gmail.com>
diff --git a/Doc/library/unittest.mock.rst b/Doc/library/unittest.mock.rst
index 6daf0fe..b76ae71 100644
--- a/Doc/library/unittest.mock.rst
+++ b/Doc/library/unittest.mock.rst
@@ -1418,7 +1418,7 @@
     >>> test_function()
 
 If :func:`patch.multiple` is used as a context manager, the value returned by the
-context manger is a dictionary where created mocks are keyed by name:
+context manager is a dictionary where created mocks are keyed by name::
 
     >>> with patch.multiple('__main__', thing=DEFAULT, other=DEFAULT) as values:
     ...     assert 'other' in repr(values['other'])