[Fix] Add missing rspamd_logger require in rules/misc.lua

- Fixes luacheck warning W113 (accessing undefined variable)
- rspamd_logger used in conditional registration logic

rules/misc.lua

@@ -21,6 +21,7 @@ local fun = require "fun"
 local rspamd_util = require "rspamd_util"
 local rspamd_parsers = require "rspamd_parsers"
 local rspamd_regexp = require "rspamd_regexp"
+local rspamd_logger = require "rspamd_logger"
 local lua_util = require "lua_util"
 local bit = require "bit"
 local rspamd_url = require "rspamd_url"