fix: gron output with special chars

[danielgtaylor]

This simplifies the PathBuffer (and makes it a bit more inefficient) to generally lower complexity and ensure the correct output for fields containing ., ], or " characters in their name.

Fixes #217

[codecov]

Codecov Report

Merging #221 (98245d9) into main (2c85909) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #221      +/-   ##
==========================================
- Coverage   76.94%   76.92%   -0.03%     
==========================================
  Files          26       26              
  Lines        3670     3666       -4     
==========================================
- Hits         2824     2820       -4     
  Misses        639      639              
  Partials      207      207              

Files	Coverage Δ
cli/content.go	74.28% <100.00%> (ø)
cli/gron.go	100.00% <100.00%> (ø)

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