[docs] [issue13790] In str.format an incorrect error message for list, tuple, dict, set

Terry J. Reedy added the comment: PR-18690 makes the approved change of 'string' to 'specification'. After merging, I will re-review the other changes in i13790b.diff and possibly make another PR for review. ---------- versions: +Python 3.9 -Python 2.7, Python 3.6 _______________________________________ Python tracker https://bugs.python.org/issue13790 _______________________________________