Make ChangeTracker#newLineCharacter public, to avoid having to pass newLineCharacter around as a parameter

[ghost]

Noticed in many code fixes that we have functions with both a ChangeTracker and newLineCharacter as parameters. ChangeTracker already stores newLineCharacter as a property, so we can just make that property public (still internal though) and access that.

[amcasey]

I agree that it would be nice to track the newline character in fewer places, but it's not intuitively obvious to me why the ChangeTracker would be the appropriate place to keep the definitive copy. It looks like it's already on the context (twice?) and, in fact, that's where the change tracker gets it. Other than some cleanup in insertNodeAtConstructorStart and insertNodeAtClassStart, I'm not sure how this change improves consistency or reduces redundancy.

[ghost]

The idea was that ChangeTracker should be the one responsible for dealing with text, while an individual refactor / code fix should only be responsible for dealing with nodes. This still wasn't the case, though, if they needed to access newLineCharacter. So I just pushed a new commit changing ChangeTracker's methods to not take newLineCharacter at all, thus it can be private again.

In addition the following are now only used publicly by tests: useNonAdjustedStartPosition, useNonAdjustedEndPosition, prefix, and suffix, and the replaceNodeRange method. We should consider just removing those tests if this is functionality we don't need to be public. The user of ChangeTracker shouldn't care about these, ChangeTracker should be able to figure out what options are appropriate given the nodes involved.

[amcasey]

Nice! I like this approach much better. (I did not carefully review the new textChanges functions.)