Update Arkansas tax logic parameters, variables, and tests

[rickecon]

• make format and make documentation has been run. (You may also want to run make test.)

This PR updates Arkansas tax logic parameters, variables, and tests.

[codecov]

Codecov Report

Attention: Patch coverage is 73.62637% with 24 lines in your changes missing coverage. Please review.

Project coverage is 98.23%. Comparing base (9461e32) to head (aacad55).
Report is 227 commits behind head on main.

Files with missing lines	Patch %	Lines
...ome/ar_income_tax_before_non_refundable_credits.py	50.00%	6 Missing and 2 partials ⚠️
...ates/ar/tax/income/credits/ar_low_income_credit.py	46.66%	6 Missing and 2 partials ⚠️
...v/states/ar/tax/income/ar_high_income_reduction.py	72.72%	2 Missing and 1 partial ⚠️
...dits/other_credits/ar_metabolic_disorder_credit.py	0.00%	2 Missing ⚠️
...credits/other_credits/ar_stillborn_child_credit.py	0.00%	1 Missing ⚠️
...eductions/itemized/mt_state_local_tax_deduction.py	0.00%	1 Missing ⚠️
...gov/states/mt/tax/income/main/mt_taxable_income.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #88      +/-   ##
==========================================
- Coverage   98.45%   98.23%   -0.23%     
==========================================
  Files        1906     1953      +47     
  Lines       28007    28723     +716     
  Branches      141      150       +9     
==========================================
+ Hits        27575    28216     +641     
- Misses        403      473      +70     
- Partials       29       34       +5     

Flag	Coverage Δ
unittests	98.23% <73.62%> (-0.23%)	⬇️

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