private int getChildIndex(ProgramNode parent, Group group) {
		Group[] kids = parent.getModule().getChildren();
		for (int i = 0; i < kids.length; i++) {
			if (group == kids[i]) {
				return i;
			}
		}
		return -1;
	}
Generate a fragment name; if there is a symbol at the start
of the fragment, and if it is user defined, then use the label 
as the fragment name; otherwise, just use the address as the name.
@param addr first address of fragment

@return String name of fragment
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/ProgramDnDTree.java