@Override
	public int compare(Bookmark bm1, Bookmark bm2) {
		String bt1 = bm1.getTypeString();
		String bt2 = bm2.getTypeString();
		String bc1 = bm1.getCategory();
		String bc2 = bm2.getCategory();
		int typeCompare = bt1.compareTo(bt2);
		if (typeCompare == 0) {
			return bc1.compareTo(bc2);
		}
		return typeCompare;
	}
Comparator for bookmarks.
@param bm1 first bookmark
@param bm2 second bookmark
@return a negative integer, zero, or a positive integer as the
	       first argument is less than, equal to, or greater than the
	       second.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/listing/BookmarkComparator.java