Fix comment

src/main.rs

@@ -62,7 +62,7 @@ impl BikeBuilder {
     }
     /// Builds the bike from the builder.
     ///
-    /// Will panic if the builder configuration is not correct
+    /// Will return an error is the bike builder misses parts
     pub fn build(self) -> Result<Bike, String> {
         match (self.wheels, self.transmission, self.brakes) {
             (Some(w), Some(t), Some(b)) => Ok(Bike {