clean up error messages

src/main.rs

@@ -78,7 +78,7 @@ fn parse_config(conf: String, pool: &mut Vec<robot::Robot>) -> Result<world::Wor
     let mut lines: Vec<&str> = conf.split('\n').collect();
     let raw_world = match ConfParser::parse(Rule::world, lines.remove(0)) {
         Ok(s) => s.as_str(),
-        Err(e) => return Err(format!("{}", e)),
+        Err(e) => return Err(String::from("World config is broken.")),
     };
     let mut w: Vec<i32> = Vec::with_capacity(2);
     for n in raw_world.split_whitespace() {
@@ -95,7 +95,7 @@ fn parse_config(conf: String, pool: &mut Vec<robot::Robot>) -> Result<world::Wor
         }
         let raw_setup = match ConfParser::parse(Rule::robot_init, lines.remove(0)) {
             Ok(s) => s.as_str(),
-            Err(e) => return Err(format!("{}", e)),
+            Err(e) => return Err(String::from("Robot setup is broken.")),
         };
 
         let rand_instructions = gen_random_instructions();