Many broken links since site re-design

Just two random examples that I've run into:

- https://matrix.org/docs/projects/bot/matterbridge.html
- https://matrix.org/blog/2018/06/15/this-week-in-matrix-2018-06-15/ (see also #450)

Was any work done to redirect existing URLs to their new locations and were these just missed, or was it not considered at all? Because it's quite frustrating to have a lot of the URLs break for no apparent reason (and URLs are supposed to be permanent).

Start by checking the two reported URLs and the site's redirect handling, then compare the findings with issue #450. Identify which legacy paths still fail after the redesign. Done means the reported URLs and other affected existing URLs resolve to their new locations.

Written by the indexing model from the issue text.