once more: documentation search indexing

Hi,

in a recent twitter discussion [1] $subject again has been brought
up. Unsurprisingly - it's still awful.

It's been brought up many times before:
- https://www.postgresql.org/message-id/CA%2BOCxoyVwmmZkWUJCez2hCqa89iGv%3Dvq58NF1yQkTg9gtpkn%3Dg%40mail.gmail.com
- https://www.postgresql.org/message-id/CAHyXU0wu7w%3DOpeHtvpei4J9SAr7TTmdRJOyCWF6MRXpQcFNHGw%40mail.gmail.com
- https://www.postgresql.org/message-id/CANNMO%2B%2BkxJmaaB7X6hq_8SqcEruySZrF%3DUkcPm-EG1JCKVascw%40mail.gmail.com
- https://www.postgresql.org/message-id/38c68b83-30ae-c039-acd0-9e853997edc4@2ndquadrant.com
- https://www.postgresql.org/message-id/560614CA.1080304@mail.com
- ...

One issue around the topic is that we seem to get bogged down in finding
a perfect solution to how to present "versioned document" to google,
preventing us from making small incremental adjustments. Since it seems
unlikely that we'll get a perfect solution anytime soon (we'd have found
it already), I'd like to try to see if we can find a way to agree on
some incremental steps.

Suggested small steps:

- add a docs/current link to https://www.postgresql.org/docs/. Often
enough that's what a user wants anyway, and it's not useful to add
additional steps for users and search engines to navigate to
docs/current/.

I can see us either making it a separate row in the versioned table,
or to split the most recent released version's link into a /current/
and $major link.

- put version in page titles where it makes sense. E.g. change
"PostgreSQL: Documentation: 10: 6.1. Inserting Data" to
"PostgreSQL 10 Documentation: 6.1. Inserting Data"

The current ordering doesn't seem like it has much going for it, and
it can't help search engines to have the version number people might
search for removed from the product name.

Right now this seem to contribute to less than helpful titles in
search engine results. Searching anonymously for "postgres alter
table" I get the less than helpful "Documentation: 12: ALTER TABLE -
PostgreSQL" on google.

It might also be worth to go a bit further and put the documentation
version *after* the page title, given that it's most likely already
clear to the reader that this is about postgres. I.e. something like
"ALTER TABLE - Documentation for PostgreSQL 14"

- Consider removing chapter numbers from page titles. I'd argue that the
particular chapter number for content isn't interesting as the title. E.g.
https://www.postgresql.org/docs/12/plpgsql-declarations.html#PLPGSQL-DECLARATION-PARAMETERS
has a title of "PostgreSQL: Documentation: 12: 42.3. Declarations"

(see also previous item). The 42.3 piece seems pointless in a title of
a website - although the actual chapter name could be helpful, because
it's not immediately obvious that the page refers to plpgsql.

- Add a meta description - even just including what we have for the
og:description thing seems like it would often be better what google
is kind of forced to make up?

Greetings,

Andres Freund

[1] https://twitter.com/samokhvalov/status/1403410028334256128