It's built as part of the code (in case the Registration screen is custom set to a different page) so it's not as simple as just finding the link and removing the /.

It's pretty straight forward. Back-up your database, back-up your site, copy the 4.8.2 upgrade package over your current site, rename your web.config to something else, copy the connection strings, machine keys, and any other web.config customizations you've done into the release.config and save it as web.config, and finally hit your site. The upgrade process should fire and install the new scripts. Check out http://www.mitchelsellers.com/Blogs/tabid/54/articleType/ArticleView/articleId/76/Upgrading-to-DotNetNuke-451-from-4x.aspx for a good tutorial on it (he may have a more up to date one but the process is still the same).