Where there's an f-string that has a debug expression in the last line of a file, the debug expression buffer is one character too short. For example:

```python3cpythonon mainviaCv14.0.3-clangvia 🐍pyenv3.11.3took15s ❯cattmp/t.pyprint(f'''{3=}''')%cpythonon mainviaCv14.0.3-clangvia 🐍pyenv3.11.3 ❯ ./python.exetmp/t.py33

A fix is already up as part ofgh-105828, so just opening this to track the issue.

Linked PRs

• gh-105831: Fix NEWS blurb from gh-105828 #105833