executors: add C++23 support

[Xyene]

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 50.58%. Comparing base (315ede5) to head (bb44787).

Files with missing lines	Patch %	Lines
dmoj/executors/CPP23.py	0.00%	6 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #1173       +/-   ##
===========================================
- Coverage   82.56%   50.58%   -31.99%     
===========================================
  Files         146      147        +1     
  Lines        5666     5672        +6     
===========================================
- Hits         4678     2869     -1809     
- Misses        988     2803     +1815     

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