re-evaluate issue 1977, direct to specific version

Consider issue 1977.

"/libs/asio should redirect to /latest not the latest version by number"

It seems a problem with this, is that it takes the web visitor to a long url .../latest/... which by itself is not problematic, and /libs/asio will always take you to the right page in the future.

However an issue arises when you continue navigating from there, and click further links, to other pages. All of them will be /latest/ too, right? Naturally.

So you end up at a "deep link" such as https://www.boost.org/doc/libs/latest/doc/html/boost_asio/reference.html. This page is not guaranteed to be "evergreen". It might not exist in 5 years. If anyone copy-pastes this link, it may eventually be wrong.

Meanwhile, if you do the opposite of issue 1977, and link to a specific version number, then the link will be https://www.boost.org/doc/libs/1_90_0/doc/html/boost_asio/reference.html. This will not ever be missing.

And so it's a real reason to revert issue 1977. If you have comments, please discuss further.