Documentation is generally considered one of the stronger points of rust libraries. Crates.io is not a documentation site you want https://docs.rs/ for that though it is generally linked to on crates.io. A lot of bigger crates also have their own online books for more in depth stuff. It is not that common to find a larger crate with bad documentation.
One specific example I encountered was ndarray. I couldn’t figure out how to make a function take an array and an arrayslice without rewriting the function for both types. This could be because I’m novice with the language, but it didn’t seem obvious. I ended up giving up after trying to dig through the docs for a few hours and went back to C++.