Improve 404 page

[GeckoEidechse]

It would be nice if the 404 page which looks like this atm

would serve links to potentially relevant pages. This could be achieved by for example searching for all pages with a name that is similar to the path of the page that was looked up.

This means that a 404 caused by e.g. a broken link cause a page was moved around in the docs would no longer result in a "roadblock" but rather would give the user option as to where to look further.