bpo-31861: Complete the C-API docs for PyObject_GetAiter and PyAiter_Check (GH-25004)

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 4e2e58e..5cb1df9 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -71,6 +71,7 @@
 
    Note: Unlike :func:`iter`, :func:`aiter` has no 2-argument variant.
 
+   .. versionadded:: 3.10
 
 .. function:: all(iterable)
 
@@ -97,6 +98,7 @@
    iterator. If *default* is given, it is returned if the iterator is exhausted,
    otherwise :exc:`StopAsyncIteration` is raised.
 
+   .. versionadded:: 3.10
 
 .. function:: any(iterable)