[FIX] Apply Ruff fix to docs/gallery.

[genedan]

Summary of Changes

This is my first time trying a stacked pull request, #1290 is the base. This one covers all the gallery docs, looking at the notebook diffs doesn't look too bad actually, I was worried we'd have a giant set of unreadable raw diffs.

Related GitHub Issue(s)

#1216

Additional Context for Reviewers

Checklist

• I passed tests locally for both code (uv run pytest) and documentation changes (uv run --directory docs jb build . --builder=custom --custom-builder=doctest)

---

Note

Low Risk
Documentation-only formatting in gallery notebooks with no production code changes.

Overview
Reformats all docs/gallery Jupyter notebooks to match Ruff style: double-quoted strings, wrapped long lines, consistent spacing around operators, and tidier matplotlib/pipeline call layouts. A few notebooks drop redundant imports (e.g. duplicate chainladder imports) and minor comment tweaks (## → #).

pyproject.toml drops the per-file Ruff ignore overrides that existed only for those gallery paths, since the notebooks now comply.

Notebook logic is unchanged aside from cosmetic edits; plot_capecod_onlevel no longer leaves the return value of intermediate pipe.fit(...) calls as cell output, while plotting still uses named_steps.model.ultimate_ as before.

^{Reviewed by Cursor Bugbot for commit 165f6b2. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Pyright Type Completeness

View the full pyright --verifytypes output for this commit

Project (full chainladder package, at this PR's head): 15.4% of exported symbols fully typed (213 / 1381)

	Known	Ambiguous	Unknown	Total
Project (head)	213	111	1057	1381

Other symbols referenced but not exported by chainladder: 13

	Known	Ambiguous	Unknown	Total
Other (head)	3	1	9	13

Symbols without documentation:

• Functions without docstring: 325
• Functions without default param: 0
• Classes without docstring: 10

Patch (exported symbols added or changed by this PR): no exported symbol type-completeness changes detected.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.67%. Comparing base (2054a10) to head (165f6b2).

Additional details and impacted files

@@             Coverage Diff              @@
##           gd_ruff_fix    #1292   +/-   ##
============================================
  Coverage        91.67%   91.67%           
============================================
  Files               93       93           
  Lines             5443     5443           
  Branches           704      704           
============================================
  Hits              4990     4990           
  Misses             328      328           
  Partials           125      125           

Flag	Coverage Δ
unittests	91.67% <ø> (ø)

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