Links do not properly render their docs' documentation

I created this simple block called `admonition`:

``` elisp
(org-defblock
admonition (type nil title nil)
nil
"Enclose text in a box denoting an admonition.

== HTML ==

In HTML, this creates a \\=`section' element with the class
admonition-TYPE, where TYPE is the main arg. Under it is a
\\=`h3'--TYPE and TITLE are included (the latter only if it
is specified).

By default, no styling is applied; it has to be done
manually. This can be done with a stylesheet applying a
style to the right class.

\(fn TYPE [:title TITLE])"
(pcase backend
('html
(let* ((prefix (capitalize (or type "note")))
(title (if title (format "%s: %s" prefix title)
prefix)))
(format "

%s

%s"
type title contents)))))
```

Then I use it in my Org file:

``` org
doc:org-block/admonition

#+begin_admonition notice
Right now, Foo is the only site supported by {{{name}}}. This will likely change in the future when this project has taken shape and is out of alpha.
#+end_admonition
```

When I hover my mouse over the doc link, I get this tooltip:

> [org-block/admonition] org-block/admonition ::
>
> (fn ARG0 ARG &rest ARGS)

The result of

``` elisp
(org-docs-get "org-block/admonition")
```

returns something equally useless. So what's the problem? Am I doing something wrong or is this a bug?