Add monotile to polgyon examples

[mo271]

This adds an aperiodic monotile to the many examples in the documentation of the polygon2d function. https://arxiv.org/abs/2303.10798

📚 Description

📝 Checklist

• I have made sure that the title is self-explanatory and the description concisely explains the PR.
• I have linked an issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

[mkoeppe]

Nice. Add the reference to the doc?

[codecov-commenter]

Codecov Report

Patch coverage has no change and project coverage change: -0.02 ⚠️

Comparison is base (c00e6c2) 88.62% compared to head (e9e52ea) 88.61%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #35331      +/-   ##
===========================================
- Coverage    88.62%   88.61%   -0.02%     
===========================================
  Files         2148     2148              
  Lines       398855   398855              
===========================================
- Hits        353480   353435      -45     
- Misses       45375    45420      +45     

Impacted Files	Coverage Δ
src/sage/plot/polygon.py	97.72% <ø> (ø)

... and 25 files with indirect coverage changes

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[github-actions]

Documentation preview for this PR is ready! 🎉
Built with commit: e9e52ea