Revert "Use mul_add with a float inversion instead of mul_neg_add"

[Shnatsel]

This caused a dramatic performance regression on ARM (NEON) on Apple Silicon.

Reverts #57

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.82%. Comparing base (7b15bc2) to head (3242122).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #59   +/-   ##
=======================================
  Coverage   99.82%   99.82%           
=======================================
  Files          13       13           
  Lines        2258     2261    +3     
=======================================
+ Hits         2254     2257    +3     
  Misses          4        4           

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