(concord-kanbun-word-class-canonical-p): New function.

(concord-kanbun-word-class-canonical-p): New function.
(concord-kanbun-add-word-class): Use `<-subcategory@misc' instead of
`<-subcategory' for non-canonicalized word-classes.
(concord-kanbun-add-morpheme): Use function
`concord-kanbun-word-class-canonical-p'; use `->entry@morpheme/misc'
and `->entry@morpheme/canonical/misc' for entry-object if a morpheme
does not have canonicalized word-class.