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.

module:hook("message/host", function (event)
	local stanza = event.stanza;
	if #stanza.tags == 1 and stanza.tags[1].attr.xmlns == "http://jabber.org/protocol/chatstates" then
		return true;
	end
end, -10);