fix: replace 3 bare except clauses with except Exception

[haosenwang1018]

Replace bare except clauses with except Exception.

---

Note

Low Risk
Low risk: only narrows doctest error handling from catching all throwables to catching standard exceptions, without changing core logic or APIs.

Overview
Updates doctests/query_em.py to replace three bare except: blocks with except Exception: in query examples that fall back when certain Redis query syntaxes are unsupported, avoiding catching non-exception throwables (e.g., KeyboardInterrupt, SystemExit) while keeping the same fallback behavior.

^{Written by Cursor Bugbot for commit 326c6cc. This will update automatically on new commits. Configure here.}

[petyaslavova]

LGTM.