pkcs1 crate has no examples, no obvious way of using

The docs for pkcs1 have no examples how to use the crate to decode an RsaPrivateKey.

The crate has a DecodeRsaPrivateKey trait, but pkcs1::RsaPrivateKey does not implement it? (or if it does, then only indirectly via a blanket impl on a pkcs8 feature in another crate???)

This seems very weird. Is that a mistake? Why is the type and trait in the same crate if they don't work together?

The only apparent way of creating pkcs1::RsaPrivateKey is via TryFrom<&[u8]> implementation, which is not mentioned anywhere, and the impl itself has zero documentation, so it needs diving into the crate's source code to discover it takes DER.

It's weird that the pkcs1 crate has a pem Cargo feature, and describes possibility of using PEM format, but as far as I can tell, PEM decoding is not supported by the crate.

Start with the pkcs1 docs for RsaPrivateKey and DecodeRsaPrivateKey, then inspect the TryFrom<&[u8]> implementation and the pem Cargo feature described in the issue. Determine and document the supported decoding paths, including whether DER and PEM are handled and how the trait relates to the type. Done means the docs include a working usage example and explain the relevant feature behavior.