fix: move cursor up / down error

[LucasXu0]

If the current path ends with 0, then use its parent path as the previous path.

[codecov]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 72.22%. Comparing base (2903792) to head (816fb3c).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/src/extensions/position_extension.dart	60.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #961      +/-   ##
==========================================
- Coverage   72.23%   72.22%   -0.01%     
==========================================
  Files         318      318              
  Lines       15099    15102       +3     
==========================================
+ Hits        10907    10908       +1     
- Misses       4192     4194       +2     

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