Improve debian/ubuntu repo instruction usability

[sim642]

I've noticed that often in #weechat even when linked to https://weechat.org/download/debian/ fail to understand what they're supposed to do in order to get newer versions on debian/ubuntu. The step-by-step instructions on that page are on the bottom. When newbies are hit with that page starting with the long list of distros they are shocked and don't realize there's any instructions at the bottom.

Therefore I suggest moving the instructions to the top of the page or somehow else making them easily found for someone looking at the page for the first time. It is not very often that someone needs to see the list first thing on the page as only experienced enough users will have any use for it.