fix renumbering for last shot

fn.py

@@ -414,11 +414,13 @@ def renumber_keep_existing(fo, offset=10):
         print('-->', idx, fs.path)
 
         if idx == last_idx: # handle last
+            print('last >>', fs.path)
+            print(ct)
             if idx > 0:
                 prev = fsl[idx-1]
                 num = get_num(prev)
                 if num is not None:
-                    break
+                    add_fileslot_number(fs, num + offset)
                 else:
                     add_fileslot_number(fs, ct)
             else: