Endpoint /+apidoc doesn't work without a trailing /

[Ines Almeida]

Some of the documentation links to `https://launchpad.net/+apidoc` for the API reference which currently doesn't work. Adding a trailing '/' does work.

I updated the URL in a couple of the documentation pages for now, but it would be better to fix the endpoint to go to the page with or without the trailing '/'

[Colin Watson (cjwatson)]

This is probably a recent regression due to the launchpad-assets refactoring.