Fix llrb tree error

[humdrum]

What this PR does / why we need it:

• Correct incorrectly ported code.
• Set "inout" for the Node parameter to apply changes.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Additional documentation:

Checklist:

• Added relevant tests or not required
• Didn't break anything

[myupage]

Thank you!

[codecov]

Codecov Report

Attention: 114 lines in your changes are missing coverage. Please review.

Comparison is base (b1d58ea) 42.58% compared to head (43763e4) 42.44%.
Report is 4 commits behind head on main.

Files	Patch %	Lines
Tests/Integration/TreeIntegrationTests.swift	0.00%	99 Missing ⚠️
Sources/Document/CRDT/CRDTTree.swift	0.00%	10 Missing ⚠️
Sources/Util/LLRBTree.swift	86.95%	3 Missing ⚠️
Sources/Document/Json/JSONTree.swift	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #147      +/-   ##
==========================================
- Coverage   42.58%   42.44%   -0.14%     
==========================================
  Files         104      104              
  Lines       24276    24326      +50     
==========================================
- Hits        10338    10326      -12     
- Misses      13938    14000      +62     

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