Rename `node_index` to n2

Convert_Matlab/overlap_v6.py

@@ -33,8 +33,8 @@ with open(f"edgelist_{orientation}.csv", "w", newline = '') as edgelist:
 
             try:
                 # Try processing id_child_1 as an array:
-                for node_index in id_child_1:
-                    writer.writerow((n1, node_index))
+                for n2 in id_child_1:
+                    writer.writerow((n1, n2))
             except TypeError:
                 # id_child_1 is a scalar int.
                 writer.writerow((n1, id_child_1))