After which ctrl+f " in" takes you to the correct chapters. I do agree that a direct link would be more helpful.
And for learning postgresql I agree it isn't very helpful - using their tutorial links, w3schools or something like udemy if you prefer video format is the way to go in that use case.
I remember back when you were told to learn to work with the documentation, not memorize it, because you will always have access to it as a reference. Maybe bookmarking reference books/documentation will make a come back as the search engines degrade.