Swapping version numbers doesn't keep you at the API you're looking at

[GuySartorelli]

When you're looking at some API, and then swap versions, it kicks you back up to the namespaces page instead of showing you the new version of the API you were looking at.

e.g.

1. go to https://api.silverstripe.org/4/SilverStripe/CMS/Model/SiteTree.html
2. swap to "5.x"
3. You should be taken to https://api.silverstripe.org/5/SilverStripe/CMS/Model/SiteTree.html but instead you're taken to https://api.silverstripe.org/5/index.html

PRs

• ENH try to stay on current page if switching versions #112

[andrewandante]

Attempted via PR to Doctum: code-lts/doctum#60 - though notably this is a pure JS implementation, whereas we are using jQuery, though I think that's covered in #108