lib: Add API docs
lib: Add API docs

Though I still don't know how to create a link.

mlundblad/geocode-glib,zeenix/geocode-glib,zeenix/geocode-glib,zeenix/geocode-glib,Distrotech/geocode-glib,Distrotech/geocode-glib,mlundblad/geocode-glib,mlundblad/geocode-glib