ci: clarify parser diff comments

[matthewevans]

No description provided.

[gemini-code-assist]

Code Review

This pull request introduces structured grouping and visual markers for different change kinds in the coverage report markdown output. It adds helper methods to the ChangeKind enum, refactors the rendering logic into a new function render_cluster_sections, and includes comprehensive regression tests to verify the grouping and marker logic. The reviewer suggests an optimization to avoid double iteration in the rendering function to improve readability and adhere to idiomatic Rust practices.

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[gemini-code-assist]

This function iterates over the clusters slice twice for each ChangeKind: once to count the items and again to render them. While not a major performance issue given the expected size of clusters, this can be made more readable and idiomatic by collecting the relevant clusters for each kind into a Vec first. This avoids the repeated filtering and makes the intent clearer.

    for kind in CHANGE_KIND_ORDER {
        let kind_clusters: Vec<_> = clusters.iter().filter(|c| c.kind == kind).collect();
        if kind_clusters.is_empty() {
            continue;
        }

        let signature_count = kind_clusters.len();
        let signature_label = if signature_count == 1 {
            "signature"
        } else {
            "signatures"
        };
        let _ = writeln!(
            s,
            "#### {} ({} {})
",
            kind.section_heading(),
            signature_count,
            signature_label,
        );

        for c in kind_clusters {
            let card_label = if c.cards.len() == 1 { "card" } else { "cards" };
            let _ = writeln!(
                s,
                "- **{} {}** · {} {}",
                c.cards.len(),
                card_label,
                c.kind.marker(),
                describe(c),
            );
            if show_cards {
                let cards: Vec<&str> = c.cards.iter().take(3).map(String::as_str).collect();
                let more = c.cards.len().saturating_sub(cards.len());
                let _ = write!(s, "  - Affected (first 3): {}", cards.join(", "));
                if more > 0 {
                    let _ = write!(s, " (+{more} more)");
                }
                s.push('\n');
            }
        }
        s.push('\n');
    }

References

1. The style guide (pillar 1) emphasizes using idiomatic Rust and standard library idioms to their fullest. The suggested change improves efficiency and readability by avoiding a double iteration pattern over the same data. ^(link)

[github-actions]

Parse changes introduced by this PR

✓ No card-parse changes detected.