[MAINTENANCE] Add links to correct API type documentation in book

[distransient]

Description

At the moment afaict there are a total of two API documentation links in the book, one for Animation "Definition" which links to the docs.rs documentation, and another on the Introduction page which always links to the master branch docs, even if you're on the "Latest Release" book. None of the type names in the book have API links.

Reason

Users expect once they've navigated to either the "latest" or "master" areas to be kept there, but there's currently no mechanism for this.

Impact

Might be a large PR depending on execution.

Additional Information

There are a few ways in which this can be remedied.

1. Javascript added to mdbook output that adds/rewrites correct type api doc links to type names (unfavorable)
2. Implement a custom mdbook compilation step with our own preprocessor that adds/rewrites correct type api doc links to type names
3. Wait for/implement rust-lang-nursery/mdBook#760 and use an environment variable during compilation to hand in a url prefix for docs

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Feel free to comment if this ticket is still relevant.