src: matrix: Rewrite misleading error message

src/matrix.rs

@@ -180,7 +180,7 @@ pub async fn login_and_sync(
                     }
                 },
                 Err(e) => {
-                    panic!("Broadcast channel is lagging: {e:?}");
+                    panic!("Broken channel: {e:?}");
                 }
             }
         }