main: return anyhow Result

This was trying to fix a bogus clippy warning on nightly about useless return in
main, that didn't work but it's slightly better than unwrap? maybe?

src/main.rs

@@ -1,19 +1,23 @@
 // recursion limit can be removed when we bump rustc requirement to 1.70
 #![recursion_limit = "256"]
 
+use anyhow::Result;
+
 mod args;
 mod ircd;
 mod matrirc;
 mod matrix;
 mod state;
 
 #[tokio::main]
-async fn main() {
+async fn main() -> Result<()> {
     env_logger::init();
     // ensure args parse early
     let _ = args::args();
 
     let ircd = ircd::listen().await;
 
-    ircd.await.unwrap();
+    ircd.await?;
+
+    Ok(())
 }