Drop the "-rust" from the "libsignal-protocol" crate

The project corresponds to libsignal-protocol-java and the others, but
/within/ the language we don't need to tag with the language name.

rust/protocol/tests/support/mod.rs

@@ -3,7 +3,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 //
 
-use libsignal_protocol_rust::*;
+use libsignal_protocol::*;
 use rand::{rngs::OsRng, CryptoRng, Rng};
 
 pub fn test_in_memory_protocol_store() -> InMemSignalProtocolStore {