docs(issue): encourage concrete code examples as evidence

Rule 2 (validated-or-flagged) now suggests dropping in a fenced code
snippet where it sharpens the point — the input that triggers the
failure or the call as it should behave — preferred over a prose
paraphrase.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

issue/SKILL.md

@@ -50,6 +50,15 @@ These apply to every issue, on create and on edit.
      `parser.rs:84` and the repro below."
    - Flagged: "Claim (unverified): the regression likely landed in
      0b96983; not yet bisected."
+   - Where it sharpens the point, drop in a concrete code example —
+     the snippet that triggers the failure, or the call as it
+     *should* behave. A fenced block beats a prose paraphrase:
+
+     ````
+     ```rust
+     parse("a\"b") // => None, want Some("a\"b")
+     ```
+     ````
 
 3. **Imperative, concise title.** Verb-first, one line, no trailing
    period — scannable in the list, mirroring commit-message style.