Feature: protoTargetLength equals accuracyMultiplyBy, targetLength

[jmsck55]

-- New feature:

atom accuracyMultiplyBy = 4 / 3

targetLength *= accuracyMultiplyBy

-- in functions using protoTargetLength

https://github.com/jmsck55/eunumber/blob/main/eunumber/minieun/MultiplicativeInverse.e#L341