Add support for the Logtalk language

[pmoura]

I noticed a single failed test, apparently due to use of a cell magic in the sample notebook. The cell magic is specific to the Logtalk kernel. Your help is most appreciated on how best to fix this test failure. Thanks.

========================================================================================================= FAILURES =========================================================================================================
_________________________________________________________________________________ test_ipynb_to_Rmd[ipynb_logtalk/logtalk_notebook.ipynb] __________________________________________________________________________________

ipynb_file = '/Users/pmoura/jupytext/tests/data/notebooks/inputs/ipynb_logtalk/logtalk_notebook.ipynb', no_jupytext_version_number = None

    def test_ipynb_to_Rmd(ipynb_file, no_jupytext_version_number):
>       assert_conversion_same_as_mirror(ipynb_file, "Rmd", "ipynb_to_Rmd")

/Users/pmoura/jupytext/tests/functional/round_trip/test_mirror.py:53: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/Users/pmoura/jupytext/src/jupytext/compare.py:441: in assert_conversion_same_as_mirror
    compare(actual, expected)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

actual = "---\njupyter:\n  kernelspec:\n    display_name: Logtalk\n    language: logtalk\n    name: logtalk_kernel\n---\n\n# An...\n\n:- end_object.\n```\n\n## Sample query\n\n```{logtalk vscode={'languageId': 'logtalk'}}\nack::ack(2, 4, V).\n```\n"
expected = "---\njupyter:\n  kernelspec:\n    display_name: Logtalk\n    language: logtalk\n    name: logtalk_kernel\n---\n\n# An...\n\n:- end_object.\n```\n\n## Sample query\n\n```{logtalk vscode={'languageId': 'logtalk'}}\nack::ack(2, 4, V).\n```\n"
actual_name = 'actual', expected_name = 'expected', return_diff = False

    def compare(
        actual, expected, actual_name="actual", expected_name="expected", return_diff=False
    ):
        """Compare two strings, lists or dict-like objects"""
        if actual != expected:
            diff = difflib.unified_diff(
                _multilines(expected),
                _multilines(actual),
                expected_name,
                actual_name,
                lineterm="",
            )
            if expected_name == "" and actual_name == "":
                diff = list(diff)[2:]
            diff = "\n".join(diff)
            if return_diff:
                return diff
>           raise AssertionError("\n" + diff)
E           AssertionError: 
E           --- expected
E           +++ actual
E           @@ -9,7 +9,7 @@
E            # An implementation of the Ackermann function
E            
E            ```{logtalk vscode={'languageId': 'logtalk'}}
E           -%%load ack.lgt
E           +% %%load ack.lgt
E            
E            :- object(ack).

/Users/pmoura/jupytext/src/jupytext/compare.py:50: AssertionError
===================================================================================================== warnings summary =====================================================================================================
../../../usr/local/Caskroom/miniconda/base/envs/jupytext-dev/lib/python3.13/site-packages/sphinx_gallery/sphinx_compatibility.py:71
  /usr/local/Caskroom/miniconda/base/envs/jupytext-dev/lib/python3.13/site-packages/sphinx_gallery/sphinx_compatibility.py:71: RemovedInSphinx80Warning: The alias 'sphinx.util.status_iterator' is deprecated, use 'sphinx.util.display.status_iterator' instead. Check CHANGES for Sphinx API modifications.
    status_iterator = sphinx.util.status_iterator

tests/external/jupyter_fs/test_jupyter_fs.py::test_jupytext_jupyter_fs_metamanager
  /usr/local/Caskroom/miniconda/base/envs/jupytext-dev/lib/python3.13/site-packages/traitlets/traitlets.py:3615: DeprecationWarning: metadata {'per_key_traits': <traitlets.traitlets.Dict object at 0x11e3b60a0>} was set from the constructor. With traitlets 4.1, metadata should be set using the .tag() method, e.g., Int().tag(key1='value1', key2='value2')
    super().__init__(trait=trait, default_value=default_value, **kwargs)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
================================================================================================= short test summary info ==================================================================================================
FAILED tests/functional/round_trip/test_mirror.py::test_ipynb_to_Rmd[ipynb_logtalk/logtalk_notebook.ipynb] - AssertionError: 
=========================================================================== 1 failed, 3129 passed, 161 skipped, 2 warnings in 187.05s (0:03:07) ============================================================================

[github-actions]

Thank you for making this pull request.

Did you know? You can try it on Binder: or .

Also, the version of Jupytext developed in this PR can be installed with pip:

HATCH_BUILD_HOOKS_ENABLE=true pip install git+https://github.com/pmoura/jupytext.git@add_logtalk_language_support

(this requires nodejs, see more at Developing Jupytext)

[pmoura]

Doing further testing, notice that conversions to hydrogen and rmd are incorrect when cell magic is present (e.g., %%load). Opening the file as a notebook strips the first % from cell magic, breaking it.