snify crashes without language extension.

[kohlhase]

when I call snify on a file likeorig.exam.tex I get the error:

The selected files input other files. Should I include those as well? [y/N]: y
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/__main__.py", line 113, in <module>
    cli()
    ~~~^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/.venv/lib/python3.13/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/.venv/lib/python3.13/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/.venv/lib/python3.13/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/.venv/lib/python3.13/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/.venv/lib/python3.13/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/__main__.py", line 103, in snify_actual
    snify(files, filter, ignore, focus)
    ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/controller.py", line 521, in snify
    unfinished = controller.run()
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/controller.py", line 244, in run
    if not self.ensure_cursor_selection():
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/controller.py", line 420, in ensure_cursor_selection
    selection_cursor = self.find_next_selection()
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/controller.py", line 471, in find_next_selection
    match = self.get_verb_trie(self.get_current_lang()).find_first_match(
            ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/controller.py", line 235, in get_verb_trie
    self._verb_trie_by_lang[lang] = VerbTrie(lang, self.linker)
                                    ~~~~~~~~^^^^^^^^^^^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/selection.py", line 236, in __init__
    words = [str(w) for w in string_to_stemmed_word_sequence_simplified(verb, lang)]
                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/stemming.py", line 55, in string_to_stemmed_word_sequence_simplified
    words.append(mystem(match.group(), lang))
                 ~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/Users/kohlhase/vc/git/github.com/sLaTeX/stextools/stextools/snify/stemming.py", line 33, in mystem
    raise ValueError(f"Unsupported language: {lang}")
ValueError: Unsupported language: exam

renaming the file to orig.exam.en.tex solves the problem. But snify should die more gracefully or just give a warning and assume english (or even ask for confirmation).