Revise card search documentation for Rush Duel [ci skip]

[kevinlul]

Closes #468

[kevinlul]

Preview changes properly at https://github.com/DawnbrandBots/bastion-bot/blob/docs/docs/card-search.md

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 47.10%. Comparing base (b8f4deb) to head (dab5fdd).
Report is 18 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #479      +/-   ##
==========================================
+ Coverage   46.77%   47.10%   +0.33%     
==========================================
  Files          35       35              
  Lines        4840     4840              
  Branches      245      159      -86     
==========================================
+ Hits         2264     2280      +16     
+ Misses       2575     2560      -15     
+ Partials        1        0       -1     

Flag	Coverage Δ
unit	47.10% <ø> (+0.33%)	⬆️

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[AlphaKretin]

The most recent change is my own, so you should also double-check it, but with that complete it looks good

[kevinlul]

Awesome, thank you! GitHub pull requests now show a side-by-side comparison of old and new images, so it's interesting to see that side-by-side.