Don't redirect to /404 when encountering a 404

[Freso]

Redirecting to /404 causes a number of issues, most importantly (for me): the visitor can't see what page they were trying to get to, which in turns means they can't slightly alter the URL (e.g., if there's a stray ) or ! or something from whatever linked them there).

Showing the 404 page content and sending a HTTP 404 response should be enough, no need to redirect away from the URL the visitor was trying to get to.