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

Thanks to Inada Naoki
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index f63a853..7a2802d 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -1057,7 +1057,7 @@
 
 .. 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