Anchors missing on some pages

[greg0ire]

I wanted to easily copy a link to a title in a documentation page, such as https://www.doctrine-project.org/contribute/index.html#coding-standard-check, and couldn't find any, although such handy anchors are present for instance on https://www.doctrine-project.org/projects/doctrine-orm/en/stable/tutorials/pagination.html

The code responsible for this seems to be here: https://github.com/doctrine/doctrine-website/blob/a009d284d1a4200a503a0f0bc31384f3905d0f36/lib/Docs/RST/RSTPostBuildProcessor.php#L141-L148