void next() {
		Address nextAddress = getNextAddress();
		if (nextAddress != null) {
			goTo(nextAddress);
		}
	}
Called from the dialog when the "next diff" button is hit.
Update the buttons in the dialog according to whether there is
a next or previous.
Ghidra/Features/ProgramDiff/src/main/java/ghidra/app/plugin/core/diff/DiffController.java