Python implementation of `functools.reduce` accepts keyword arguments, while the C implementation does not

Bug report

Bug description:

Steps to reproduce:

printf '*disabled*\n_functools\n' > Modules/Setup.local
./configure --with-pydebug && make -j
./python
Python 3.14.0a0 (heads/main:dc03ce797a, Jul 13 2024, 09:31:53) [GCC 13.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import functools
>>> functools.reduce(function=lambda x, y: x + y, sequence=[1, 2, 3, 4, 5])
15

Our docs mention functools.reduce as a function that accepts positional-only arguments.

I have a PR ready to fix that.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

gh-121676: Raise a DeprecationWarning if the Python implementation of functools.reduce is called with a keyword args #121677