strptime: use %r in error messages, not %s

Bug report

Bug description:

Consider the following example, say I'm parsing a date string read from an external source, and I forgot to call .strip():

from datetime import datetime

datetime.strptime("2001-02-03\n", "%Y-%m-%d")

The output is a little confusing:

$ python3 strptime_example.py
Traceback (most recent call last):
  File "strptime_example.py", line 3, in <module>
    datetime.strptime("2025-11-14\n", "%Y-%m-%d")
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_strptime.py", line 789, in _strptime_datetime
    tt, fraction, gmtoff_fraction = _strptime(data_string, format)
                                    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/_strptime.py", line 558, in _strptime
    raise ValueError("unconverted data remains: %s" %
                      data_string[found.end():])
ValueError: unconverted data remains: 

The error message is using %s, when using %r would give a more unambiguous description of the extra data – similar with strings quoted manually using ' in the error message just above:

https://github.com/python/cpython/blob/a486d452c78a7dfcd42561f6c151bf1fef0a756e/Lib/_strptime.py#L567-L570

CPython versions tested on:

3.13

Operating systems tested on:

macOS

Linked PRs

• gh-141541
• gh-141712

Commencez dans Lib/_strptime.py autour de l’erreur de données non converties aux lignes citées dans le rapport, et reproduisez l’exemple avec le saut de ligne final. Le travail est terminé lorsque les données restantes sont affichées sans ambiguïté à l’aide d’un formatage de type repr, cohérent avec le message d’erreur adjacent.