docs: correct showspikes hovermode description

[CAOShurong]

Fixes the documentation part of #7595.

The showspikes description claimed:

Note: This only takes affect when hovermode = closest

but this is not accurate. Spikes are drawn in all cartesian hovermodes:

• src/components/fx/hover.js (the second spike-point block, when hoverData.length !== 0) filters hover points by point.xa.showspikes / point.ya.showspikes regardless of which of x, y, x unified, y unified or closest is active — only the snap target differs (cursor position vs. nearest data point).
• The repo's own test suite asserts spikelines render with hovermode: 'x': test/jasmine/tests/hover_spikeline_test.js cases around L506-521 expect 4 spikeline elements after hovering in x mode.

Change: replaces the incorrect note with a per-hovermode description:

Determines whether or not spikes (aka droplines) are drawn for this axis. In closest hovermode, spikes are only drawn when hovering near a data point. In x, y, x unified, and y unified hovermodes, spikes are also drawn at the current cursor position on the axis.

Docs-only change to one attribute description in src/plots/cartesian/layout_attributes.js; no behavior change, so no new tests and no changelog entry beyond this fix.

[emilykl]

Hi @CAOShurong, thanks for working on this attribute description.

The correction isn't quite accurate: when showspikes is true, spikes are drawn according to the behavior specified by spikesnap (which defaults to drawing spikes at the closest data point).

Can you adjust the attribute description to read:

            'Determines whether or not spikes (aka droplines) are drawn for this axis.',
            'Note that spikes will never be drawn when `hovermode` is *false*.'

[CAOShurong]

Addressed the requested documentation wording in commit 874b63b13.

• showspikes now uses the exact requested description: spikes are never drawn when hovermode is false.
• Regenerated test/plot-schema.json entries and updated the draftlog.
• node --check src/plots/cartesian/layout_attributes.js, JSON parsing of test/plot-schema.json, and git diff --check pass.

The branch is ready for re-review. AI assistance remains disclosed in the PR body.

[CAOShurong]

Follow-up in commit d5f9474b6: the branch is now rebased onto the current PR base and includes the generated TypeScript schema description plus the generator-compatible no-final-newline form of test/plot-schema.json.

This addresses the two generated-artifact checks that were red on the previous push. The remaining red jobs in that run were the repository's flaky flaky-no-gl-jasmine and test-baselines image comparison (map_symbol-text), unrelated to this docs-only change.

git diff --check and local JavaScript/JSON syntax checks pass; ready for re-review.

[CAOShurong]

The follow-up head 77fc50325c3b5d7e26465196cca2a675120531f1 now has a fully successful CI run, including schema/type-generation and all Jasmine/baseline jobs. The exact requested showspikes wording is in place and the branch is ready for re-review.

[emilykl]

@CAOShurong Thanks for the update, this looks ready to go.

FWIW, I don't see a disclosure of AI assistance in the PR description. We don't require disclosure of AI assistance, but we do ask that changes related to plot interactivity or visuals are thoroughly verified in the browser before opening a PR.