Fix docs.rs SLH-DSA link in README (#958)

Author: daxpedda

README.md

@@ -20,7 +20,7 @@ and can be easily used for bare-metal or lightweight WebAssembly programming.
 | [`lms`] | [Leighton-Micali Signature](https://datatracker.ietf.org/doc/html/rfc8554) | [![crates.io](https://img.shields.io/crates/v/lms-signature.svg)](https://crates.io/crates/lms-signature) | [![Documentation](https://docs.rs/lms-signature/badge.svg)](https://docs.rs/ed25519) | [![lms build](https://github.com/RustCrypto/signatures/actions/workflows/lms.yml/badge.svg)](https://github.com/RustCrypto/signatures/actions/workflows/lms.yml)
 | [`ml-dsa`] | [Module Lattice DSA](https://csrc.nist.gov/pubs/fips/204/final) | [![crates.io](https://img.shields.io/crates/v/ml-dsa.svg)](https://crates.io/crates/ml-dsa) | [![Documentation](https://docs.rs/ml-dsa/badge.svg)](https://docs.rs/ml-dsa) | [![lms build](https://github.com/RustCrypto/signatures/actions/workflows/ml-dsa.yml/badge.svg)](https://github.com/RustCrypto/signatures/actions/workflows/lms.yml)
 | [`rfc6979`] | [Deterministic (EC)DSA Signatures](https://datatracker.ietf.org/doc/html/rfc6979) | [![crates.io](https://img.shields.io/crates/v/rfc6979.svg)](https://crates.io/crates/rfc6979) | [![Documentation](https://docs.rs/rfc6979/badge.svg)](https://docs.rs/rfc6979) | [![rfc6979 build](https://github.com/RustCrypto/signatures/actions/workflows/rfc6979.yml/badge.svg)](https://github.com/RustCrypto/signatures/actions/workflows/rfc6979.yml)
-| [`slh-dsa`] | [Stateless Hash-Based Signature](https://csrc.nist.gov/pubs/fips/205/final) | [![crates.io](https://img.shields.io/crates/v/slh-dsa.svg)](https://crates.io/crates/slh-dsa) | [![Documentation](https://docs.rs/slh-dsa/badge.svg)](https://docs.rs/ed25519) | [![slh-dsa build](https://github.com/RustCrypto/signatures/actions/workflows/slh-dsa.yml/badge.svg)](https://github.com/RustCrypto/signatures/actions/workflows/slh-dsa.yml)
+| [`slh-dsa`] | [Stateless Hash-Based Signature](https://csrc.nist.gov/pubs/fips/205/final) | [![crates.io](https://img.shields.io/crates/v/slh-dsa.svg)](https://crates.io/crates/slh-dsa) | [![Documentation](https://docs.rs/slh-dsa/badge.svg)](https://docs.rs/slh-dsa) | [![slh-dsa build](https://github.com/RustCrypto/signatures/actions/workflows/slh-dsa.yml/badge.svg)](https://github.com/RustCrypto/signatures/actions/workflows/slh-dsa.yml)
 
 NOTE: for RSA signatures see <https://github.com/RustCrypto/RSA>