[docs](trx-plugin-example): update paths and references

Update dependency paths to new trx-backend and trx-frontend
locations. Replace trx-bin references with trx-server/trx-client.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>

examples/trx-plugin-example/src/lib.rs

@@ -15,7 +15,7 @@ use trx_frontend::{register_frontend, FrontendSpawner};
 const BACKEND_NAME: &str = "example";
 const FRONTEND_NAME: &str = "example-frontend";
 
-/// Entry point called by trx-bin when the plugin is loaded.
+/// Entry point called by trx-server/trx-client when the plugin is loaded.
 #[no_mangle]
 pub extern "C" fn trx_register() {
     register_backend(BACKEND_NAME, example_backend_factory);