I think the names of the different log file name formats could be
improved a lot.  There's basically nothing that tells the ordinary user
what the different log formats imply.  Attached is a patch which changes
the name to be more verbose about what the formats mean.

Note that I have used #channel instead of "target" or "buffer" in this
patch, because the ordinary user will most likely understand that
#channel could very well be an IRC user as well.