gh-160139: Format configparser and its tests with ruff format (#160265)

* gh-160139: Format `configparser` and its tests with `ruff format`

`Lib/configparser.py` and `Lib/test/test_configparser.py` are synced
periodically with the `configparser` backport on PyPI, which runs
`ruff format`. Nearly all of the divergence between the two copies was
line wrapping and call-argument layout, reconciled by hand on every
sync, and an upstream change landing inside a block the backport had
rewrapped surfaced as a conflict even when the change itself was
trivial.

Run `ruff format` with the settings the backport uses -- preview style,
`quote-style = "preserve"` and ruff's default line length -- so that
both copies agree on layout and the sync carries only the genuine
compatibility deltas. No behavior changes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* gh-160139: Wrap the two lines `ruff format` leaves long

The formatter does not rewrap comments or docstring text, so a docstring
line in `_read` and a commented-out assertion in `test_no_first_section`
stayed over the line length. Wrap both by hand; no text changes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: jaraco