Migrate the asciidoc based reference documentation to Antora https://antora.org/. The new documentation site https://docs.spring.io/spring-framework/reference/ provides more structured content, an integrated search, a link to "edit this page", multiple versions with option to switch, a warning at the top of older versions, and more.
For more details on the Antora integration for Spring projects, see https://github.com/spring-io/antora-ui-spring. It is also the right place to report issues related to the user interface.