ci(triage): detect harness test attributes, not just #[test]

The needs-tests detector matched an added `#[test]` or `#[cfg(test)]` line
and nothing else, so it missed every test written with a harness attribute.
That is most of this repo: 345 `#[tokio::test]` and 189 `#[sqlx::test]`
against 540 bare `#[test]`. Any PR whose tests are all DB or async tests got
labeled needs-tests, which is what happened on #275 (three added
`#[sqlx::test]` functions) and #262 (eight).

Match an added attribute whose last path component contains `test`, followed
by `]` or `(`. That covers the four forms in the tree today and the harnesses
a contributor might reach for later (`#[rstest]`, `#[test_case]`,
`#[wasm_bindgen_test]`) without enumerating them.

Deliberately not keying on an added `assert!`: a production assertion is
ordinary Rust, so that signal would let a testless PR clear the label
silently. The label is a nudge, so it should fail loud. Labeling a PR that
did add tests gets corrected by the author; clearing one that did not is
invisible.

Anchoring to the start of the added line also drops three false positives the
old `.*` prefix accepted: a comment, a string literal, and a doc example that
merely mention `#[test]`.

Verified against the real patches of 14 open PRs: #275 and #262 stop being
labeled, both of which do add tests, and no other verdict changes.

Author: beardthelion

.github/workflows/pr-triage.yml

@@ -70,9 +70,23 @@ jobs:
             const changedRust = names.some(n => n.startsWith("crates/") && n.endsWith(".rs"));
             // A test can live in a tests/ dir, a *_test.rs file, or (the common Rust
             // pattern) an inline #[test] / #[cfg(test)] block added inside the source file.
+            // Match an added attribute whose last path component contains `test`,
+            // followed by `]` or `(`. That covers the four forms in the tree today
+            // (#[test], #[tokio::test], #[tokio::test(flavor = ...)], #[sqlx::test])
+            // and the harnesses a future contributor might reach for without naming
+            // them one by one (#[rstest], #[test_case], #[wasm_bindgen_test]).
+            //
+            // Deliberately NOT keying on an added assert!/assert_eq!: a production
+            // assertion is ordinary Rust, so that signal lets a testless PR clear the
+            // label silently. This heuristic is only a nudge, so it should fail in the
+            // loud direction -- labeling a PR that did add tests gets corrected by the
+            // author, while clearing one that did not is invisible.
+            //
+            // Anchored to the start of the added line, so a comment or a string that
+            // merely mentions #[test] does not count.
             const addsInlineTest = files.some(f =>
               f.filename.endsWith(".rs") && f.patch &&
-              /^\+.*#\[(test\]|cfg\(test\))/m.test(f.patch));
+              /^\+\s*#\[(cfg\(test\)|(?:\w+::)*\w*test\w*[\](])/m.test(f.patch));
             const touchedTests =
               names.some(n => n.includes("/tests/") || n.endsWith("_test.rs")) || addsInlineTest;
             if (changedRust && !touchedTests) want.add("needs-tests");