lib: Refer to docs/ folder in module docs.

Author: har7an

src/lib.rs

@@ -8,7 +8,8 @@
 //! <strong>⚠️ Warning:</strong> The cross library is for internal
 //! use only: only the command-line interface is stable. The library
 //! may change at any point for any reason. For documentation on the
-//! CLI, please see the repository <a href="https://github.com/cross-rs/cross">README</a>
+//! CLI, please see the repository <a href="https://github.com/cross-rs/cross">README</a>,
+//! <a href="https://github.com/cross-rs/cross/tree/main/docs">docs folder</a>
 //! or the <a href="https://github.com/cross-rs/cross/wiki">wiki</a>.
 //! </p>