Make the offers module non-public

As the `offers` types in LDK are currently only practically useful
for VLS users, there's no need to rush to get them included in
bindings, and sadly some tweaks to the bindings generator are
required for them.

For now, its simpler to just make them non-public.

Author: TheBlueMatt

lightning/src/lib.rs

@@ -78,7 +78,7 @@ extern crate core;
 pub mod util;
 pub mod chain;
 pub mod ln;
-pub mod offers;
+pub(crate) mod offers;
 pub mod routing;
 pub mod onion_message;
 pub mod blinded_path;