printString reimplementations look suspicious

[Ducasse]

We should revisit the printString implementations because it looks like some of them are simply printOn: disguised.

In addition some of them promote bad pattern:

MalGraphEdge >> printString

^ self from printString, ' -> ', self to printString

Why do we create two substreams instead of sharing the printString via printOn:?
Here printString each time create a stream then .... it is worse , create spurious copies...
Super super ugly.

In general printOn: in general should not call printString, better use self print: str
So may be we can open another issue for this issue.

[Ducasse]

Thanks this is cool :)