Wikitextparser

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- Fixed a bug in ``WikiText.external_links`` not detecting external links inserted via overwriting a template string. (74)
- The following already deprecated functions/parameters are removed:

- Setting ``Parameter.default`` to ``None`` is not possible anymore. Use ``del Parameter.default`` instead.
- The default value for ``preserve_spacing`` parameter of ``Template.set_arg`` is now ``False``. (It was deprecated to call this method without providing a value for ``preserve_spacing``)
- The ``pattern`` parameter of ``WikiList.sublists``, ``WikiList.get_lists`` and ``WikiText.get_lists`` cannot be ``None`` anymore. Use the default value instead.
- ``WikiText.lists and ``WikiText.tags`` are removed. Use ``get_lists or ``get_tags`` instead.

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- Fixed a bug in ``plain_text()``/``remove_markup``, not being able to handle table with row/colspan. (116)
- ``plain_text()`` will now include table captions.

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- Fixed a syntax error for Python < 3.10.

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- BREAKING CHANGE: dropping Python 3.6 support.
- Fixed error in getting ``plain_text()`` of emptied-out wikitext (113)
- Deprecated: Calling ``Template.set_arg()`` without specifying a value for ``preserve_spacing`` parameter is deprecated.
This is a temporary warning in preparation for changing the default value of this parameter from ``True`` to ``False``. (111)
- Fixed the ``stacklevel`` of warnings.
- New feature: ``plain_text()`` replaces wiki-tables with a TSV string. (115)

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- Fixed a bug in detecting `reverse pipe tricks <https://en.wikipedia.org/wiki/Help:Pipe_trick#Reverse_pipe_trick>`_ as wikilinks.

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- Fixed a bug in ``WikiText.external_links`` causing external links within extension tags (e.g. ref tag) not to be detected when tag is inside a template/parser function/parameter. (110)