Improve move instructions

[zenangst]

• Don't produce move instructions if old and new index are equal

[codecov-io]

Codecov Report

Merging #22 into master will increase coverage by 0.14%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #22      +/-   ##
=========================================
+ Coverage   66.66%   66.8%   +0.14%     
=========================================
  Files           9       9              
  Lines         237     238       +1     
=========================================
+ Hits          158     159       +1     
  Misses         79      79

Impacted Files	Coverage Δ
Source/Shared/Algorithm.swift	92.75% <100%> (+0.05%)	⬆️

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