Fix deprecation warning in latexify_rst_text.

[hugobuddel]

Fixes

PendingDeprecationWarning: Argument "writer_name" will be removed in Docutils 2.0. Specify writer name in the "writer" argument.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 29.89%. Comparing base (e386ea5) to head (fe3295f).

❗ There is a different number of reports uploaded between BASE (e386ea5) and HEAD (fe3295f). Click for more details.

HEAD has 147 uploads less than BASE

Flag	BASE (e386ea5)	HEAD (fe3295f)
	149	2

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #939       +/-   ##
===========================================
- Coverage   75.17%   29.89%   -45.29%     
===========================================
  Files          70       68        -2     
  Lines        9024     8861      -163     
===========================================
- Hits         6784     2649     -4135     
- Misses       2240     6212     +3972     

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[hugobuddel]

Yeah what is this,

FAILED scopesim/tests/tests_reports/test_rst_utils.py::TestLatexifyRstText::test_stuff - AssertionError: passed string "latex" as "writer" parameter; pass an instance, or use the "writer_name" parameter instead (in docutils.core.publish_* convenience functions).

Oh well. I don't know whether there is a version of docutils where both arguments work without complaints, but I'm not going to look for it. Let's leave this open and merge it when we move to docutils 2.