Also carbon-copy messages of type "normal"

It makes no sense to restrict carbon-copying to "chat" messages.  Other servers [copy "normal" messages][1], too, and XEP-0280 [is expected][2] to be updated accordingly.

[1]: http://hg.prosody.im/prosody-modules/file/a68ec7a2dc02/mod_carbons/mod_carbons.lua#l35
[2]: http://mail.jabber.org/pipermail/standards/2014-November/029321.html