Fix :forms metadata not appearing in 'info' response

In standard Clojure's `doc` function `:forms` metadata has a priority over `:arglists` metadata when displaying the documentation. CIDER's Elisp side also has capabilities for that, but for some reason `cider.nrepl.middleware.info/var-meta-whitelist` is missing `:forms`, so Elisp side never receives `:forms` metadata for a symbol.

Example:

```clojure
(defn foobar
  {:forms '([foo])}
  ([foo] foo)
  ([foo bar] (+ foo bar)))
```

`C-c C-d d` before patch:
```
test.core/foobar
([foo] [foo bar])
```

`C-c C-d d` after patch:
```
test.core/foobar
  [foo]