feat: メッセージの変更差分の改善

[MikuroXina]

close #665

Type of Change:

機能の変更, 依存関係の更新

Details of implementation (実施内容)

メッセージの変更差分を, 行ごとで変更があった箇所を強調表示する仕組みに変えました.

[m1sk9]

手が滑りました

[codecov-commenter]

Codecov Report

Merging #669 (1ff204e) into main (8cf8bc1) will increase coverage by 0.02%.
The diff coverage is 74.07%.

@@            Coverage Diff             @@
##             main     #669      +/-   ##
==========================================
+ Coverage   72.53%   72.56%   +0.02%     
==========================================
  Files          67       67              
  Lines        4683     4691       +8     
  Branches      440      443       +3     
==========================================
+ Hits         3397     3404       +7     
+ Misses        849      847       -2     
- Partials      437      440       +3     

Flag	Coverage Δ
unittests	72.56% <74.07%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/service/difference-detector.ts	81.94% <68.18%> (+0.69%)	⬆️
src/model/judging-status.ts	48.83% <100.00%> (ø)
src/service/command/meme/ojaru.ts	82.35% <100.00%> (ø)
src/service/command/meme/takopi.ts	83.33% <100.00%> (ø)
src/service/command/party.ts	81.89% <100.00%> (ø)

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[m1sk9]

LGTM
eslint が typeof 演算子に () をつける件についてはこっちでちゃんと調べてみます