fixture function `makepyfile` does not encode files properly

makepyfile is ignoring the encoding parameter, in both pytester and testdir fixtures.

found the issue working on windows with cp1252 encoding and using pytest-doctestplus.

i traced the issue to makepyfile, arguments and kwargs are passed unpacked.

 make_file = testdir.makepyfile(
            f"""
            def f():
                '''
                >>> print('{a}')
                {b}
                '''
                pass
            """.encode(encoding=encoding),
            encoding=encoding, # will be packed into `files` and default utf-8 encoding will be used
        )

$ python --version
Python 3.13.2

$ pip freeze
colorama==0.4.6
iniconfig==2.0.0
packaging==24.2
pluggy==1.5.0
pytest==8.3.3

Start in src/_pytest/pytester.py at makepyfile, then compare how the pytester and testdir fixtures pass arguments and keyword arguments into it. Check the existing tests around these fixtures and add coverage for a non-UTF-8 encoding such as cp1252. Done means the encoding parameter is honored by both fixtures when creating files.