You can't ipfs.add a path

Fixes ipfs-inactive/js-ipfs-http-client#722

Author: olizilla

SPEC/FILES.md

@@ -16,7 +16,6 @@ Where `data` may be:
 - a [`Buffer instance`][b]
 - a [`Readable Stream`][rs]
 - a [`Pull Stream`][ps]
-- a Path (caveat: will only work in Node.js)
 - a URL
 - an array of objects, each of the form:
 ```JavaScript