Improve generated documentation for typedef

[DartBot]

This issue was originally filed by [email protected]

---

The documentation generated for typedefs is pretty unhelpful. Consider:

http://api.dartlang.org/docs/continuous/dart_html/ErrorCallback.html

(I've attached a screenshot as well.) There is no information about ErrorCallback. What would be really great is to show the signature.

---

Attachment:
[Screen Shot 2012-08-17 at 5.52.12 PM.png](https://storage.googleapis.com/google-code-attachments/dart/issue-4582/comment-0/Screen Shot 2012-08-17 at 5.52.12 PM.png) (115.11 KB)

[johnniwinther]

There is already a CL for this, waiting for commit.

---

Set owner to @johnniwinther.
Added Started label.

[johnniwinther]

Fixed in r11024.

---

Added Fixed label.