document IOBase.__del__'s behavior (closes #21764)
Patch from Nikolaus Rath.
diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index be20884..7b40085 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -346,6 +346,12 @@
is usual for each of the lines provided to have a line separator at the
end.
+ .. method:: __del__()
+
+ Prepare for object destruction. :class:`IOBase` provides a default
+ implementation of this method that calls the instance's
+ :meth:`~IOBase.close` method.
+
.. class:: RawIOBase