Do you know a language other than Rust that has alternative for docs.rs? In JavaScript and Python they never bother to have any documentation or reference, one notable example that gets me frustrated these days is the openai SDK for TypeScript. There is no documentation for it. I have to go look at the source code to figure out what the hell goes on.
javadoc.io is similar to (but not as good as) docs.rs for the Java ecosystem. It pulls the JavaDoc out of packages that are published to the Maven Central repository. It doesn't have good discoverability like docs.rs, though, and it's dependent on the publishers actually including the javadoc files.
javadoc.io is similar in the fact that it lists things I guess? It looks worse (objective) but is also depended on a lot less so is just by default going to be a second thought. It’s also not auto-generated like docs.rs like you said.