redirect search engines to lists.boost.org

A google search for:

boost mailing list
or
boost mailing list archives

currently leads to https://www.boost.org/doc/libs/1_32_0/more/mailing_lists.htm

SOLUTION:

Add pattern matching logic so that any url with a path

`/doc/libs/.*/more/mailing_lists.htm`

includes a canonical reference in the header section:

``

to "https://lists.boost.org/mailman3/lists/"

Further analysis:

A canonical link already appears, which is

```

```

And it varies from the warning at the top of the page

` This is an older version of Boost and was released in 2013. The current version is 1.90.0.`

These should be consolidated. The second of these is more sophisticated, as it realizes https://www.boost.org/doc/libs/latest/more/mailing_lists.htm doesn't exist. (Recently added by Dave. That is great!) It doesn't attempt to forward the user to a failed link, but instead goes to "/libraries/latest/" which is a good fallback. The canonical link ought to also say "/libraries/latest/". The canonical link should match the latest version link. I will open another issue to address this.

Returning to the current issue...

Create an exceptional case. Both the canonical link and the current version link, which should be the same as each other, check on a special case. If it matches `/doc/libs/.*/more/mailing_lists.htm` , those links go to `https://lists.boost.org/mailman3/lists/`.