x/pkgsite: change browser URL to canonical path #40936
Description
If the URL passed to the frontend is path@version.
it resolves this internally to module@version/suffix.
and all the links it puts on the page have this form. However, the
browser URL still says "path@version".
We could use window.history.replaceState to change the browser URL without a page reload. According to
https://computerrock.com/blog/html5-changing-the-browser-url-without-refreshing-page, it is available in modern browsers.