private void pushGroup(ClangTokenGroup group) {
		depth += 1;
		if (depth >= nodeStack.length) {
			expand();
		}
		nodeStack[depth] = group;
		indexStack[depth] = (direction < 0) ? group.numChildren() - 1 : 0;
	}
Add a new ClangTokenGroup to the node stack
@param group is the new group being pushed
Ghidra/Features/Decompiler/src/main/java/ghidra/app/decompiler/TokenIterator.java