docs(signals): add missing diagnostic guide sections

[everton-dgn]

Eight diagnostic guide URLs point to missing sections. Four codes share combined headings, and four newer codes have no section yet.

Add individual sections for all eight codes, preserving the existing combined headings so their links continue to work. Add a test that reads DiagnosticCode and checks that every DEV.guideUrl fragment has a matching section in the guide. It currently covers 65 codes.

Validation: the test failed for the missing sections before the documentation changes; all 32 tests in the selected diagnostics files now pass. Prettier and git diff --check pass.

[changeset-bot]

🦋 Changeset detected

Latest commit: 1c11048

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 12 packages

Name	Type
solid-js	Patch
@solidjs/diagnostics	Patch
@solidjs/element	Patch
@solidjs/h	Patch
@solidjs/html	Patch
test-integration	Patch
@solidjs/universal	Patch
@solidjs/web	Patch
todos-server-example	Patch
@solidjs/babel-plugin	Patch
@solidjs/compiler	Patch
@solidjs/signals	Patch

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[codspeed]

Merging this PR will not alter performance

✅ 188 untouched benchmarks

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_{Comparing everton-dgn:docs/diagnostic-guide-sections (1c11048) with next (6be6c51)}

[ryansolid]

Cross-checked all eight sections against the emission sites — seven are accurate, and the anchor test is a good guard (GitHub renders ### A / B as #a--b, which is exactly why those links were dead). Approved.

I pushed one commit on top of your branch (1c11048) rather than asking for another round:

• #### HUGE_FAN_IN ended with "Start with the sources listed in the message", but HUGE_FAN_IN doesn't list sources — noteFanIn emits only the computation's name and data: { count }, and it is the always-on backstop at 2000 tracked sources. The source list belongs to WIDE_SCOPE_DEPS (attribution engine, threshold 30, up to 12 names). The old combined paragraph had the same sentence, but under a HUGE_FAN_IN-specific heading it was wrong for that code. Both sections now say what each one actually reports and point at each other.
• ASYNC_OUTSIDE_LOADING_BOUNDARY had a stray hard wrap leaving "The root" alone on a line.
• SETTLE_WALK_UNINITIALIZED_SOURCE is severity error, so "hiding the warning" → "silencing the diagnostic".

Every heading is kept, the anchor test passes, prettier is clean. Your commit is untouched; this merges as soon as CI is green on the new head. Thanks for the test — it will keep the guide honest as codes are added.

— Claude via Cursor

[coveralls]

Coverage Report for CI Build 37285535127

Warning

Build has drifted: This PR's base is out of sync with its target branch, so coverage data may include unrelated changes.
Quick fix: rebase this PR. Learn more →

Coverage remained the same at 75.991%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	1195
Covered Lines:	962
Line Coverage:	80.5%
Relevant Branches:	925
Covered Branches:	649
Branch Coverage:	70.16%
Branches in Coverage %:	Yes
Coverage Strength:	27.95 hits per line

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