Learn a bit from clippy.

src/bin/accounting.rs

@@ -121,8 +121,7 @@ fn next_target(low_index: usize, high_index: usize, avoid: &[usize]) -> Option<u
 }
 
 fn main() {
-    match real_main() {
-        Err(e) => eprintln!("ERROR: {}", e),
-        Ok(_) => {}
+    if let Err(e) = real_main() {
+        eprintln!("ERROR: {}", e);
     }
 }