[a-zA-Z] matches hex digits a-f in IPv6 addresses, causing IP-only
lists like antifilter-ip6 (127k entries) to be treated as domain lists.
This triggered useless history merge (sort -u on ~2.5M lines = 77 min)
and DNS resolution attempts. Use [g-zG-Z] instead, which correctly
distinguishes domain names from IPv6 hex notation.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>