exercise/25 fix typo

exercises/25_errors5.zig

@@ -24,7 +24,7 @@ pub fn main() void {
 
 fn addFive(n: u32) MyNumberError!u32 {
     //
-    // This function needs to return any error which might come back from fix().
+    // This function needs to return any error which might come back from detect().
     // Please use a "try" statement rather than a "catch".
     //
     var x = detect(n);