doc Fix missing doc, wrong types, typos

1) make type="implements Foo" notation consistent with the other classes.
Search for `@type(.*)\.I[A-Z](.*)` in the repo, we never precede it with the Object

2) missing `$urlService` in the API docs while `$requestHandler` is there

3) typos

4) remove `@event` annotation, it's useless and not used in most of the
other files

Close #795.