Fix typo in zipfile documentation. (GH-10151)

diff --git a/Doc/library/zipfile.rst b/Doc/library/zipfile.rst
index e5872f3..8d8612a 100644
--- a/Doc/library/zipfile.rst
+++ b/Doc/library/zipfile.rst
@@ -372,7 +372,7 @@
    Return the name of the first bad file, or else return ``None``.
 
    .. versionchanged:: 3.6
-      Calling :meth:`testfile` on a closed ZipFile will raise a
+      Calling :meth:`testzip` on a closed ZipFile will raise a
       :exc:`ValueError`.  Previously, a :exc:`RuntimeError` was raised.