Fix for QRpedia URLs with extra /
Summary: When generating URLs for the Bulgarian Wikipedia, QRpedia, and more specifically bg.qrwp.org, inserts an extra slash in the path after the /wiki/ part. Thus, instead of e.g. Ботевград, the QR code leads to /Ботевград. This will likely be fixed, but as an interim solution, instead of creating a bunch of /something articles pointing to something, we may as well just employ JS to redirect the browser to the correct page. There are no legitimate pages starting with a slash, so this shouldn't break anything.
Test Plan: Tested in the browser's console and in my own user's JS.
Reviewers: Borislav, Сале
Reviewed By: Borislav
Differential Revision: https://phabricator.wikimedia.bg/D9