Offer suppression quick fixes for errors

[ViTeXFTW]

What changed

• offer the zerosyntax-disable quick fix for error diagnostics as well as warnings and hints
• retain the intentional exclusion for the unknown-suppression typo hint
• update the spec-first regression coverage and diagnostics documentation

Why

The shared quick-fix dispatcher explicitly filtered out Severity::Error, so only some diagnostic types could add a file-level disable pragma. Removing that gate makes the existing shared suppression action available consistently.

Impact

Users can suppress any error or warning code from the editor's quick-fix menu instead of editing the pragma manually.

Validation

• cargo fmt --all -- --check
• cargo test
• git diff --check

[greptile-apps]

Greptile Summary

This PR makes suppression quick fixes available for error diagnostics too. The main changes are:

• Removed the severity gate from the shared diagnostic quick-fix dispatcher.
• Kept unknown-suppression excluded from suppression quick fixes.
• Updated the quick-fix regression spec for bad-bool errors.
• Updated diagnostics docs to describe suppressing any diagnostic code.

Confidence Score: 5/5

Safe to merge with minimal risk.

The code change is narrowly scoped to the existing suppression quick-fix path, and the updated tests cover the intended error-diagnostic behavior.

No files require special attention.

T-Rex Logs

What T-Rex did

• T-Rex ran the requested contract verification as part of the pull request review.
• T-Rex noted that local artifact references were not uploaded with the verification results.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
crates/analysis/src/actions.rs	Removes the severity gate from suppression quick-fix dispatch while preserving de-duplication and the unknown-suppression exclusion.
crates/analysis/tests/spec/QuickfixSuppress.ini	Updates the fixture comment to match the new bad-bool suppression behavior.
crates/analysis/tests/spec/QuickfixSuppress.spec.toml	Changes the quick-fix expectation for bad-bool from no suppression offer to a suppression offer.
docs/diagnostics.md	Documents that suppressions apply to any diagnostic code while still recommending fixes for error-level issues.

_{Reviews (1): Last reviewed commit: "Offer suppression quick fixes for errors" | Re-trigger Greptile}