Refactor PMComplexTest >> testComplexConjugate

[olekscode]

This is the current implementation

testComplexConjugate
	| z complexConjugateOfZ expected |
	z := 5 - 6 i.
	
	complexConjugateOfZ := z complexConjugate .
	
	expected := 5 + 6 i.
	self assert: complexConjugateOfZ equals: expected.

It has many unnecessary temporary variables that make it hard to read
I propose to replace it with the following:

testComplexConjugate

	self assert: (5 - 6i) complexConjugate equals: (5 + 6i).

Same thing but more clear