Adjusted tree-recipes question to output error message when rejecting incorrect solution

Author: TianLangHin

competition/tree-recipes/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "postfix-to-prefix"
+name = "tree-recipes"
 version = "0.1.0"
 edition = "2021"
 

competition/tree-recipes/src/main.rs

@@ -137,6 +137,7 @@ fn main() {
             if provided_answer.as_str() == solution {
                 exit(0);
             } else {
+                eprintln!("Your answer was incorrect.");
                 exit(1);
             }
         }