Rename ``PMComplex >> conjugated`` to ``complexConjugate``

[olekscode]

Because numbers can also be conjugate in a different sense: 5 + 5 sqrt is conjugate to 5 - 5 sqrt.
https://math.stackexchange.com/questions/3397053/whats-the-correct-definition-of-conjugate-and-do-we-identify-them

Also, this message should be implemented by Number

5 complexConjugate.  "5"
(5 + 3i) complexConjugate. "5 - 3i"

And testing:

5 isComplexConjugateOf: 5. "true"
(5 + 3i) isComplexConjugateOf: (5 - 3i). "true"

[hemalvarambhia]

[hemalvarambhia]

I am noticing now that the Complex Number Test Class has a large number of methods. A refactor might split this up, and there are a number of ways to do that (I'll provide a list in a moment...).