docs(rust): change description of the ockam crate
-//! Ockam is a library for end-to-end encryption and mutual authentication for
-//! distributed applications.
-//!
-//! For a comprehensive introduction to Ockam, see <https://www.ockam.io/learn>.
+//! End-to-end encryption and mutual authentication for distributed applications.
+
#![deny(unsafe_code)]
#![warn(
missing_docs,
