pythongh-113212: Document zero-arg super() inside nested functions …

…and generator expressions

Doc/library/functions.rst

@@ -1800,6 +1800,13 @@ are always available.  They are listed here in alphabetical order.
    the second argument is a type, ``issubclass(type2, type)`` must be true (this
    is useful for classmethods).
 
+   When called directly within an ordinary method of a class, both arguments may
+   be omitted ("zero-argument :func:`super`"). In this case, *type* will be the
+   enclosing class, and *obj* will be the first argument of the immediately
+   enclosing function (typically ``self``). (This means that zero-argument
+   :func:`super` will not work as expected within a nested function or a generator
+   expression, which implicitly creates a nested function.)
+
    There are two typical use cases for *super*.  In a class hierarchy with
    single inheritance, *super* can be used to refer to parent classes without
    naming them explicitly, thus making the code more maintainable.  This use

Misc/NEWS.d/next/Core and Builtins/2023-12-20-08-54-54.gh-issue-113212.62AUlw.rst

@@ -0,0 +1 @@
+Improve :py:class:`super` error messages.