<Plug>(vimpire_doc_lookup) doesn't work on special forms

[SevereOverfl0w]

do, let, etc. do not work with vimpire's doc system.

[SevereOverfl0w]

https://github.com/clojure-emacs/orchard/blob/67bce174cc8b81ec6b31bbf4bd08d181567ecdc6/src/orchard/meta.clj#L98-L126 probably useful