mod_pubsub_summary: Use pre-escaped UTF-8 sequence for compat This silences a warning about using the non-existent global 'utf8' each time this line was hit. The utf8 library was introduced in Lua 5.3, so the warning would appear with 5.1 and 5.2.

---
summary: Extra verbose stanza logging
---

Summary
=======

This module logs the full stanzas that are sent and received into debug
logs, for debugging purposes.