Typedoc markdown

We weren't properly formatting `@typedoc` information. See the `Enumerable` protocol docs for an example (http://elixir-lang.org/docs/stable/Enumerable.html#t:acc/0).

Not clear on a good way to test this. Most of the autolinking functions are tested down a level from the main link call, which didn't catch that we were not autolinking an entire class of documentation.