Fix rendered module docs

Currently we have docs for public modules in two places and these are
joined together when rendered as HTML.

Remove the rustdoc strings from `lib.rs` and defer to the modules for
the module level docs.

src/hrp.rs

@@ -1,4 +1,6 @@
 // SPDX-License-Identifier: MIT
 
+//! Re-exports the hrp types from [`primitives::hrp`] to make importing ergonomic for the top level APIs.
+
 #[doc(inline)]
 pub use crate::primitives::hrp::{Hrp, BC, BCRT, TB};

src/lib.rs

@@ -141,11 +141,8 @@ extern crate alloc;
 extern crate core;
 
 mod error;
-/// Re-exports the hrp types from [`primitives::hrp`] to make importing ergonomic for the top level APIs.
 pub mod hrp;
-/// All the primitive types and functionality used in encoding and decoding.
 pub mod primitives;
-/// API for encoding and decoding segwit addresses.
 pub mod segwit;
 
 #[cfg(all(feature = "alloc", not(feature = "std"), not(test)))]