Update task.md

To keep that order coherent with the solution's.

6-async/03-promise-chaining/01-then-vs-catch/task.md

@@ -3,10 +3,10 @@
 Are these code fragments equal? In other words, do they behave the same way in any circumstances, for any handler functions?
 
 ```js
-promise.then(f1, f2);
+promise.then(f1).catch(f2);
 ```
 
 Versus;
 ```js
-promise.then(f1).catch(f2);
+promise.then(f1, f2);
 ```