feat: reset to the default inline code format logic

[LucasXu0]

Reset to the default inline code format: only format the inline code if the input text is in inline code format.

showcase.mp4

[codecov]

Codecov Report

Attention: Patch coverage is 72.72727% with 3 lines in your changes missing coverage. Please review.

Project coverage is 72.15%. Comparing base (8d3f5b9) to head (3dd7b23).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/src/core/document/text_delta.dart	72.72%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #988      +/-   ##
==========================================
- Coverage   72.17%   72.15%   -0.02%     
==========================================
  Files         319      319              
  Lines       15215    15221       +6     
==========================================
+ Hits        10981    10983       +2     
- Misses       4234     4238       +4     

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