getChildWithTagNameIterator taking String&

The recent XmlElement changes have broken a lot of our code that was using the macros.
I think the reason is that we pass juce::Identifiers in to these which have a StringRef operator so can be converted to StringRefs.

Now getChildWithTagNameIterator take a String&, this conversion doesn’t work anymore and causes a compile error. Can this be changed to StringRef to ensure compatibility with existing code? I think it will end up being stored as a String in the iterator anyway.

Sorry about that, I’ll push a fix shortly.