Typos and stale docstrings in `Lib/traceback.py`

[devdanzin]

Bug report

Bug description:

Typos and stale docstrings in Lib/traceback.py found by Claude Code using code-review-toolkit:

1. Comment typo "exc_traceback, exc_value, exc_traceback" — exc_type omitted, exc_traceback duplicated. [traceback.py:1063]
2. FrameSummary class docstring has broken grammar: "for the of code" should be "for the line of code". [traceback.py:296]
3. extract_stack docstring says items are "quadruples" — stale since Python 3.5, should reference FrameSummary objects. [traceback.py:261-268]
4. extract_tb docstring lists only 4 attributes — omits end_lineno, colno, end_colno added in 3.11. [traceback.py:78-89]
5. _display_width docstring says "extra amount of width space" — it returns total display width, not a delta. [traceback.py:976-979]

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-145896: Fix typos and stale docstrings in Lib/traceback.py #145897