Issue #16711: Fix required method names for collections.Iterator

Thanks to Inada Naoki
diff --git a/Doc/library/collections.abc.rst b/Doc/library/collections.abc.rst
index 9873489..558eb98 100644
--- a/Doc/library/collections.abc.rst
+++ b/Doc/library/collections.abc.rst
@@ -90,7 +90,7 @@
 
 .. class:: Iterator
 
-   ABC for classes that provide the :meth:`__iter__` and :meth:`next` methods.
+   ABC for classes that provide the :meth:`__iter__` and :meth:`__next__` methods.
    See also the definition of :term:`iterator`.
 
 .. class:: Sequence