[ refactor ] rename ∣∣ to ∥, ∤∤ to ∦ throughout Algebra.Definitions.RawMagma and Algebra.Properties.*.Divisibility

[ refactor ] rename ∣∣ to ∥, ∤∤ to ∦ throughout Algebra.Definitions.RawMagma and Algebra.Properties.*.Divisibility #990