refactor(yaml): remove Mark class

[timreichen]

Changes
This PR removes the Mark class and replaces it with functions.

Reasoning
Mark is only used in #createError(). It seems inefficient to instantiate a class instead of creating and returning the string directly in a function.

[codecov]

Codecov Report

Attention: Patch coverage is 73.17073% with 11 lines in your changes missing coverage. Please review.

Project coverage is 96.23%. Comparing base (c817a5a) to head (d6af634).
Report is 3 commits behind head on main.

Files	Patch %	Lines
yaml/_loader_state.ts	73.17%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5805      +/-   ##
==========================================
- Coverage   96.23%   96.23%   -0.01%     
==========================================
  Files         480      479       -1     
  Lines       38748    38727      -21     
  Branches     5616     5615       -1     
==========================================
- Hits        37291    37269      -22     
- Misses       1416     1417       +1     
  Partials       41       41              

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[iuioiua]

Nice catch. Thank you.