fix: parse special characters in LaTeX

[pep8speaks]

Hello @njzjz! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file tests/cases.py:

Line 199:80: E501 line too long (92 > 79 characters)

Comment last updated at 2024-06-30 06:40:35 UTC

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 90.47%. Comparing base (ba4babc) to head (d983ae6).

:exclamation: Current head d983ae6 differs from pull request most recent head 3d43863

Please upload reports for the commit 3d43863 to get more accurate results.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #41 +/- ## ======================================= Coverage 90.47% 90.47% ======================================= Files 12 12 Lines 420 420 ======================================= Hits 380 380 Misses 40 40 ```

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